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58    Virtual File System Manager

Palm OS® Programmer's API Reference

Palm OS® 68K SDK

     

The Virtual File System (VFS) Manager is a layer of software that manages all installed file system libraries. It provides a unified API to application developers while allowing them to seamlessly access many different types of file systems —such as VFAT, HFS, and NFS—on many different types of media, including Compact Flash, Memory Stick, and SmartMedia.This chapter provides reference material for the VFS Manager API as follows:

The header file VFSMgr.h declares the VFS Manager API. For more information on the VFS Manager, see Chapter 7, "Expansion," in Palm OS Programmer's Companion, vol. I.

Note that the VFS Manager is an optional system extension; the functions described in this chapter are implemented only if the VFS Manager Feature Set is present.

VFS Manager Data Structures ^TOP^

FileInfoType Struct ^TOP^

Purpose

The FileInfoType structure contains information about a specified file or directory. This information is returned as a parameter to VFSDirEntryEnumerate(). The structure is defined as follows:

Prototype

typedef struct FileInfoTag {
UInt32 attributes;
Char *nameP;
UInt16 nameBufLen;
} FileInfoType, *FileInfoPtr;

Fields

attributes
Characteristics of the file or directory. See File and Directory Attributes for the bits that make up this field.
nameP
Pointer to the buffer that receives the full name of the file or directory. Initialize this parameter to NULL if you don't want to receive the name.
nameBufLen
Size of the nameP buffer, in bytes.

FileRef Typedef ^TOP^

Purpose

The FileRef type is used to encode references to files and directories.

Prototype

typedef UInt32 FileRef;

VFSAnyMountParamType Struct ^TOP^

Purpose

The VFSAnyMountParamType structure is a base structure for VFSSlotMountParamType, VFSPOSEMountParamType, and other similar structures that may be defined in the future. Use one or the other according to how you set the mountClass parameter.

Prototype

typedef struct VFSAnyMountParamTag {
UInt16 volRefNum;
UInt16 reserved;
UInt32 mountClass;
} VFSAnyMountParamType;
typedef VFSAnyMountParamType 
*VFSAnyMountParamPtr;

Fields

volRefNum
The volume reference number. This is initially obtained when you successfully mount a volume. It can then be used to format a volume with VFSVolumeFormat() or unmount a volume with VFSVolumeUnmount.
reserved
Reserved for future use.
mountClass
Defines the type of mount to use with the specified volume. See Volume Mount Classes for a list of mount types.

VFSSlotMountParamType Struct ^TOP^

Purpose

The VFSSlotMountParamType structure is used when you are mounting a card located in an Expansion Manager slot. The vfsMountParam->mountClass field must be set to VFSMountClass_SlotDriver.

Prototype

typedef struct VFSSlotMountParamTag {
VFSAnyMountParamType vfsMountParam;
UInt16 slotLibRefNum;
UInt16 slotRefNum;
} VFSSlotMountParamType;

Fields

vfsMountParam
See the description of VFSAnyMountParamType for an explanation of the fields in this structure. Set vfsMountParam->mountClass to VFSMountClass_SlotDriver to mount an Expansion Manager slot.
slotLibRefNum
Reference number for the slot driver library allocated to the given slot number. Obtain this field by calling ExpSlotLibFind().
slotRefNum
Number of the slot to be mounted.

VFSPOSEMountParamType Struct ^TOP^

Purpose

The VFSPOSEMountParamType structure is used when you are mounting a volume through the Palm OS® Emulator. The vfsMountParam->mountClass must be set to VFSMountClass_POSE. Note that ordinary applications and file systems shouldn't use VFSPOSEMountParamType.

Prototype

typedef struct VFSPOSEMountParamTag {
VFSAnyMountParamType vfsMountParam; 
UInt8 poseSlotNum;
} VFSPOSEMountParamType;

Fields

vfsMountParam
See the description of VFSAnyMountParamType for an explanation of the fields in this structure. Set vfsMountParam->mountClass to VFSMountClass_POSE to mount a virtual slot.
poseSlotNum
Number of the virtual slot number to be mounted by the Palm OS Emulator.

VolumeInfoType Struct ^TOP^

Purpose

The VolumeInfoType structure defines information that is returned to VFSVolumeInfo() and used throughout the VFS functions.

Prototype

typedef struct VolumeInfoTag {
UInt32 attributes;
UInt32 fsType;
UInt32 fsCreator;
UInt32 mountClass;
UInt16 slotLibRefNum;
UInt16 slotRefNum;
UInt32 mediaType;
UInt32 reserved;
} VolumeInfoType, *VolumeInfoPtr;

Fields

attributes
Characteristics of the volume. See Volume Attributes for the bits that make up this field.
fsType
File system type for this volume. See Defined File Systems for a list of the supported file systems.
fsCreator
Creator ID of this volume's file system driver. This information is used with VFSCustomControl().
mountClass
Mount class that mounted this volume. The supported mount classes are listed under Volume Mount Classes.
slotLibRefNum
Reference to the slot driver library with which the volume is mounted. This field is only valid when the mount class is vfsMountClass_SlotDriver.
slotRefNum
Slot number where the card containing the volume is loaded. This field is only valid when the mount class is vfsMountClass_SlotDriver.
mediaType
Type of card media. See Defined Media Types in the Expansion Manager chapter for the list of values. This field is only valid when the mount class is vfsMountClass_SlotDriver.
reserved
Reserved for future use.

VFS Manager Constants ^TOP^

Defined File Systems ^TOP^

The following file systems are currently defined by the VFS Manager. These values are used with VFSVolumeInfo() in the VolumeInfoType.fsType parameter.

Constant

Value

Description

vfsFilesystemType_AFS

'afsu'

Unix Andrew file system

vfsFilesystemType_EXT2

'ext2'

Linux file system

vfsFilesystemType_FAT

'fats'

FAT12 and FAT16, which only handles 8.3 filenames

vfsFilesystemType_FFS

'ffsb'

Unix Berkeley block based file system

vfsFilesystemType_HFS

'hfss'

Macintosh standard hierarchical file system

vfsFilesystemType_HFSPlus

'hfse'

Macintosh extended hierarchical file system

vfsFilesystemType_HPFS

'hpfs'

OS2 High Performance file system

vfsFilesystemType_MFS

'mfso'

Macintosh original file system

vfsFilesystemType_NFS

'nfsu'

Unix Networked file system

vfsFilesystemType_Novell

'novl'

Novell file system

vfsFilesystemType_NTFS

'ntfs'

Windows NT file system

vfsFilesystemType_VFAT

'vfat'

FAT12 and FAT16 extended to handle long filenames

Open Mode Constants ^TOP^

This section describes constants that are used for the openMode parameter to the VFSFileOpen() function. These constants specify the mode in which a file or directory is opened.

Constant

Value

Description

vfsModeExclusive

0x0001U

Open and lock the file or directory. This mode excludes anyone else from using the file or directory until it is closed.

vfsModeRead

0x0002U

Open for read access.

vfsModeWrite

0x0004U | vfsModeExclusive

Open for write access.

vfsModeReadWrite

vfsModeWrite | vfsModeRead

Open for read/write access.

vfsModeCreate

0x0008U

Create the file if it doesn't already exist. This open mode is implemented in the VFS layer, rather than in the file system library.

vfsModeTruncate

0x0010U

Truncate the file to zero (0) bytes after opening, removing all existing data. This open mode is implemented in the VFS layer, rather than in the file system library.

vfsModeVFSLayerOnly

vfsModeCreate | vfsModeTruncate | vfsModeLeaveOpen

Mask used to isolate those flags that are only used by the VFS layer. These flags are not passed to the file system layer.

vfsModeLeaveOpen

0x0020U

Leave the file open even after the

application exits.

File and Directory Attributes ^TOP^

The constants in the following table define bits that can be used individually or in combination when setting or interpreting the file attributes for a given file or directory. See VFSFileGetAttributes(), VFSFileSetAttributes(), and the FileInfoType data structure for specific use.

Constant

Value

Description

vfsFileAttrReadOnly

0x00000001UL

Read-only file or directory

vfsFileAttrHidden

0x00000002UL

Hidden file or directory

vfsFileAttrSystem

0x00000004UL

System file or directory

vfsFileAttrVolumeLabel

0x00000008UL

Volume label

vfsFileAttrDirectory

0x00000010UL

Directory

vfsFileAttrArchive

0x00000020UL

Archived file or directory

vfsFileAttrLink

0x00000040UL

Link to another file or directory

Volume Attributes ^TOP^

The constants in the following table define bits that can be used individually or in combination to make up the attributes field in the VolumeInfoType structure.

Constant

Value

Description

vfsVolumeAttrHidden

0x00000004UL

The volume should not be visible to the user.

vfsVolumeAttrNonRemovable

0x00000008UL

The media cannot be removed.

vfsVolumeAttrReadOnly

0x00000002UL

The volume is read only.

vfsVolumeAttrSlotBased

0x00000001UL

Reserved. Check the mount class to determine how a volume is mounted.

Volume Mount Classes ^TOP^

The following constants define how a given volume is mounted. The mountClass field in the VFSAnyMountParamType and VolumeInfoType structures takes on one of these values.

Constant

Value

Description

vfsMountClass_POSE

'pose'

Mount the volume through the Palm OS Emulator. This is used for testing.

vfsMountClass_Simulator

sysFileTSimulator

Mount the volume through the simulator. This is used for testing.

vfsMountClass_SlotDriver

sysFileTSlotDriver

Mount the volume with a slot driver shared library.

Error Codes ^TOP^

The VFS Manager defines the following error codes:

Constant

Description

vfsErrBadData

The operation could not be completed because of invalid data.

vfsErrBadName

Invalid filename, path, or volume label.

vfsErrBufferOverflow

The supplied buffer is too small.

vfsErrDirectoryNotFound

Returned when the path leading up to the file does not exist.

vfsErrDirNotEmpty

The directory is not empty and therefore cannot be deleted.

vfsErrFileAlreadyExists

A file with this name exists already in this location.

vfsErrFileBadRef

The file reference is invalid: it has been closed or was not obtained from VFSFileOpen().

vfsErrFileEOF

The file pointer is at the end of the file.

vfsErrFileGeneric

Generic file error.

vfsErrFileNotFound

The file was not found at the specified location.

vfsErrFilePermissionDenied

The requested permissions could not be granted.

vfsErrFileStillOpen

Returned from the underlying file system's delete function if the file is still open.

vfsErrIsADirectory

This operation can only be performed on a regular file, not a directory.

vfsErrNameShortened

A volume name or filename was automatically shortened to conform to the file system specification.

vfsErrNoFileSystem

None of the installed file systems support this operation.

vfsErrNotADirectory

This operation can only performed on a directory.

vfsErrVolumeBadRef

The volume reference number is invalid.

vfsErrVolumeFull

There is insufficient space left on the volume.

vfsErrVolumeStillMounted

Returned from the underlying file system's format function if the volume is still mounted.

VFS Manager Functions ^TOP^

VFSCustomControl Function ^TOP^

Purpose

Make a custom API call to a particular file system, given its creator ID. You can use VFSVolumeInfo() to determine the creator ID of the file system for a given volume.

Declared In

VfsMgr.h

Prototype

Err VFSCustomControl(
   UInt32 fsCreator,
   UInt32apiCreator,
   UInt16 apiSelector,
   void*valueP,
   UInt16 *valueLenP
)

Parameters

fsCreator
Creator of the file system to call. A value of zero (0) tells the VFS Manager to check each registered file system, looking for one which supports the call.
apiCreator
Registered creator ID.
apiSelector
Custom operation to perform.
valueP
A pointer to a buffer containing data specific to the operation. On exit, depending on the function of the particular custom call and on the value of valueLenP, the contents of this buffer may have been updated.
valueLenP
On entry, points to the size of the valueP buffer. On exit, this value reflects the size of the data written to the valueP buffer. If valueLenP is NULL, valueP is passed to the file system but is not updated on exit.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
expErrUnsupportedOperation
The specified opcode and/or creator is unsupported or undefined.
sysErrParamErr
The valueP buffer is too small.
vfsErrNoFileSystem
VFS Manager cannot find an appropriate file system to handle the request.

Comments

The driver identifies the call and its API by a registered creator ID and a selector. This allows file system developers to extend the API by defining selectors for their creator IDs. It also allows file system developers to support selectors (and custom calls) defined by other file system developers.

This function must return expErrUnsupportedOperation for all unsupported or undefined opcodes and/or creators.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

VFSDirCreate Function ^TOP^

Purpose

Create a new directory.

Declared In

VfsMgr.h

Prototype

Err VFSDirCreate(
   UInt16 volRefNum,
   constChar*dirNameP
)

Parameters

volRefNum
Volume reference number returned from VFSVolumeEnumerate().
dirNameP
Pointer to the full path of the directory to be created.

Returns

Returns one of the following error codes:

errNone
No error
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrBadName
Some or all of the path, up to but not including the last component specified in the dirNameP parameter, does not exist.
vfsErrFileAlreadyExists
A file with this name already exists in this location.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.
vfsErrVolumeBadRef
The volume has not been mounted.
vfsErrVolumeFull
There is not enough space left on the volume.

Comments

All parts of the path except the last component must already exist. The vfsFileAttrDirectory attribute is set with this function.

VFSDirCreate() does not open the directory. Any operations you want to perform on this directory require a reference, which is obtained through a call to VFSFileOpen().

Compatibility

Implemented only if the VFS Manager Feature Set is present.

VFSDirEntryEnumerate Function ^TOP^

Purpose

Enumerate the entries in a given directory. Entries can include files, links, and other directories.

Declared In

VfsMgr.h

Prototype

Err VFSDirEntryEnumerate (
   FileRef dirRef,
   UInt32*dirEntryIteratorP,
   FileInfoType *infoP
)

Parameters

dirRef
Directory reference returned from VFSFileOpen().
dirEntryIteratorP
Pointer to the index of the last entry enumerated. For the first iteration, initialize this parameter to the constant vfsIteratorStart. Upon return, this references the next entry in the directory. If infoP is the last entry, this parameter is set to vfsIteratorStop.
infoP
Pointer to the FileInfoType data structure that contains information about the given directory entry. The nameP and nameBufLen fields in this structure must be initialized prior to calling VFSDirEntryEnumerate.

Returns

Returns one of the following error codes:

errNone
No error.
expErrEnumerationEmpty
There are no directory entries left to enumerate.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
sysErrParamErr
The dirEntryIteratorP is not valid.
vfsErrFileBadRef
The specified file reference is invalid.
vfsErrIsNotADirectory
The specified file reference is valid, but does not point to a directory.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.

Comments

The directory to be enumerated must first be opened with VFSFileOpen() in order to obtain a file reference. In order to obtain information on all entries in a directory you must make repeated calls to VFSDirEntryEnumerate inside a loop. Boundaries on the iteration are the defined constants vfsIteratorStart and vfsIteratorStop. Before the first call to VFSDirEntryEnumerate, dirEntryIteratorP should be initialized to vfsIteratorStart. Each iteration then changes the value pointed to by dirEntryIteratorP. When information on the last entry in the directory is returned, dirEntryIteratorP is set to vfsIteratorStop.


WARNING! Creating, renaming, or deleting any file or directory invalidates the enumeration. After any such operation, the enumeration will need to be restarted.

Example

The following code excerpt illustrates how to use VFSDirEntryEnumerate.


FileInfoType info; 
FileRef dirRef; 
UInt32 dirIterator; 
Char *fileName = MemPtrNew(256);// should check for err 
 
// open the directory first, to get the directory reference 
// volRefNum must have already been defined 
err = VFSFileOpen(volRefNum, "/", vfsModeRead, &dirRef); 
if(err == errNone) { 
 
info.nameP = fileName;// point to local buffer 
info.nameBufLen = 256; 
dirIterator = vfsIteratorStart 
while (dirIterator != vfsIteratorStop) { 
// Get the next file 
err = VFSDirEntryEnumerate (dirRef, &dirIterator,
&info); 
if (err == errNone) { 
// Do something with the directory entry information 
// Pull the attributes from info.attributes 
// The file name is in fileName 
} else { 
// handle error, possibly by breaking out of the 
loop 
} 
} else { 
// handle directory open error here 
} 
MemPtrFree(fileName); 
} 

Compatibility

Implemented only if the VFS Manager Feature Set is present.

VFSExportDatabaseToFile Function ^TOP^

Purpose

Save the specified database to a.pdb or.prc file on an external storage card.

Declared In

VfsMgr.h

Prototype

Err VFSExportDatabaseToFile (
   UInt16volRefNum,
   const Char *pathNameP,
   UInt16 cardNo,
   LocalIDdbID
) 

Parameters

volRefNum
Volume on which the destination file should be created.
pathNameP
Pointer to the complete path and name of the destination file to be created.
cardNo
Card number on which the .pdb or .prc being exported resides.
dbID
ID of the database being exported.

Returns

Returns one of the following error codes:

errNone
No error
expErrNotEnoughPower
There is insufficient battery power to perform the database export operation.
vfsErrBadName
The path name specified in pathNameP is not valid.

Comments

This utility function exports a database from main memory to a.pdb or.prc file on an external storage card. This function is the opposite of VFSImportDatabaseFromFile(). It first creates the file specified in the pathNameP parameter with VFSFileCreate(). After opening the file the Exchange Manager function ExgDBWrite() is called with an internal callback function for exporting the file from the Data Manager. The Exchange Manager makes repeated calls to this callback function, which receives the data back in blocks. Once all the data has been exported, VFS Manager closes the file.

This function is used, for example, to copy applications from main memory to a storage card.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSExportDatabaseToFileCustom(), VFSFileWrite(), VFSImportDatabaseFromFile()

VFSExportDatabaseToFileCustom Function ^TOP^

Purpose

Saves the specified database to a .pdb or.prc file on an external storage card. This function differs from VFSExportDatabaseToFile() in that it allows you to track the progress of the export operation.

Declared In

VfsMgr.h

Prototype

Err VFSExportDatabaseToFileCustom(
   UInt16volRefNum,
   const Char *pathNameP,
   UInt16cardNo,
   LocalID dbID,
   VFSExportProcPtrexportProcP,
   void *userDataP
) 

Parameters

volRefNum
Volume on which the destination file should be created.
pathNameP
Pointer to the complete path and name of the destination file to be created.
cardNo
Card number on which the .pdb or .prc being exported resides.
dbID
ID of the database being exported.
exportProcP
User-defined callback function that tracks the progress of the export. This function should allow the user to cancel the export. Pass NULL if you don't have a progress callback function. See VFSExportProcPtr() for the requirements of this function.
userDataP
Pointer to any data you want to pass to the callback function specified in exportProcP. This information is not used internally by the VFS Manager. Pass NULL if you don't have a progress callback function or if that function doesn't need any such data.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotEnoughPower
There is insufficient battery power to perform the database export operation.
vfsErrBadName
The path name specified in pathNameP is not valid.

This function can also return any error code other than errNone produced by your callback function.

Comments

This function is similar to VFSExportDatabaseToFile() in that it exports a database from main memory to a.pdb or.prc file on an external storage card. It extends the functionality by allowing you to specify a callback function that tracks the progress of the export. It first creates the file specified in the pathNameP parameter with VFSFileCreate(). After opening the file, the Exchange Manager function ExgDBWrite() is called with an internal callback function for exporting the file from the Data Manager. Exchange Manager makes repeated calls to this function, which receives the data back in blocks. The progress tracker, if one has been specified, is also called every time a new chunk of data is passed back. Once all the data has been exported, the VFS Manager closes the file.

This function is used, for example, to copy applications from main memory to a storage card.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSExportDatabaseToFile(), VFSFileWrite(), VFSImportDatabaseFromFileCustom()

VFSFileClose Function ^TOP^

Purpose

Closes a file or directory that has been opened with VFSFileOpen().

Declared In

VfsMgr.h

Prototype

Err VFSFileClose (
   FileRef fileRef
)

Parameters

fileRef
File reference number returned from VFSFileOpen().

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrFileBadRef
The specified file reference is invalid.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

VFSFileCreate Function ^TOP^

Purpose

Create a file. This function cannot be used to create a directory; use VFSDirCreate() instead.

Declared In

VfsMgr.h

Prototype

Err VFSFileCreate(
   UInt16 volRefNum,
   constChar*pathNameP
)

Parameters

volRefNum
Reference number of the volume on which to create the file. This volume reference number is returned from VFSVolumeEnumerate().
pathNameP
Pointer to the full path of the file to be created. All parts of the path, excluding the filename, must already exist.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrBadName
The pathNameP is invalid.
vfsErrFileAlreadyExists
A file with this name already exists in this location.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.
vfsErrVolumeBadRef
The volume has not been mounted.
vfsErrVolumeFull
There is not enough space left on the volume.

Comments

It is the responsibility of the file system library to ensure that all filenames are translated into a format that is compatible with the native format of the file system, such as the 8.3 convention for a FAT file system without long filename support. See Naming Files in the Expansion chapter of the Palm OS Programmer's Companion, vol. I for a description of how to construct a valid path.

This function does not open the file. Use VFSFileOpen() to open the file.

This function should not be used to create a directory. To create a directory use VFSDirCreate().

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSFileDelete()

VFSFileDBGetRecord Function ^TOP^

Purpose

Load a record from an opened.pdb file on an external card into the storage heap.

Declared In

VfsMgr.h

Prototype

Err VFSFileDBGetRecord (
   FileRef ref,
   UInt16recIndex,
   MemHandle *recHP,
   UInt8*recAttrP,
   UInt32 *uniqueIDP
)

Parameters

ref
The file reference returned from VFSFileOpen(). Note that the open file must be a .pdb file.
recIndex
The index of the record to load.
recHP
Pointer to the record data's handle in the storage heap. If NULL is returned in this parameter there is either no data in this field or an error occurred reading this data from the file. If the handle is not NULL, you must dispose of the allocated handle using MemHandleFree().
recAttrP
Pointer to the attributes of the record. The values returned are identical to the atttributes returned from DmRecordInfo(). See Record Attribute Constants in the Data and Resource Manager chapter for a description of each attribute. Pass NULL for this parameter if you do not want to retrieve this information.
uniqueIDP
Pointer to the unique identifier for this record. Pass NULL for this parameter if you do not want to retrieve this information.

Returns

Returns one of the following error codes:

errNone
No error.
dmErrIndexOutOfRange
The recIndex is out of range.
dmErrNotRecordDB
The file referenced by ref is not a record database.
memErrNotEnoughSpace
There is not enough space in memory for the requested record entry.
sysErrParamErr
A NULL value was passed in for the recHP, recAttrP, and uniqueIDP parameters.
vfsErrBadData
The local offsets (localChunkID) from the top of the.pdb to the start of the raw record data for this entry are out of order.

Comments

This function is analogous to DmGetRecord() but works with files on an external card rather than databases in main memory. This function allocates a handle of the appropriate size from the storage heap and returns it in the recHP parameter. The caller is responsible for freeing this memory, using MemHandleFree(), when it is no longer needed.


NOTE: This function is not efficient for multiple accesses and should be used sparingly.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSFileReadData()

VFSFileDBGetResource Function ^TOP^

Purpose

Load a resource into the storage heap from an opened.prc file.

Declared In

VfsMgr.h

Prototype

Err VFSFileDBGetResource (
   FileRef ref,
   DmResTypetype,
   DmResID resID,
   MemHandle *resHP
) 

Parameters

ref
The file reference returned from VFSFileOpen(). Note that the open file must be a .prc file.
type
The type of resource to load. See the Data and Resource Manager chapter for more information on resources.
resID
The ID of resource to load.
resHP
Pointer to the resource data handle that was loaded into memory.

Returns

Returns one of the following error codes:

errNone
No error.
dmErrNotResourceDB
The file referenced by ref is not a resource database.
dmErrResourceNotFound
The requested resource was not found.
memErrNotEnoughSpace
There is not enough space in memory for the requested resource entries.
sysErrParamErr
resHP is NULL.

Comments

This function locates the specified resource in the open.prc file. See the Palm OS File Format Specification for more information on the layout of.prc files.

Once the resource is found, VFSFileDBGetResource allocates a handle of the appropriate size in the storage heap and reads it into memory. The handle to this memory location is returned through the resHP parameter. The caller is responsible for freeing this memory, using MemHandleFree(), when it is no longer needed.


NOTE: This function is not efficient for multiple accesses and should be used sparingly.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

VFSFileDBInfo Function ^TOP^

Purpose

Get information about a database represented by an open.prc or.pdb file.

Declared In

VfsMgr.h

Prototype

Err VFSFileDBInfo (
   FileRef ref,
   Char *nameP,
   UInt16 *attributesP,
   UInt16 *versionP,
   UInt32*crDateP,
   UInt32 *modDateP,
   UInt32*bckUpDateP,
   UInt32 *modNumP,
   MemHandle*appInfoHP,
   MemHandle *sortInfoHP,
   UInt32 *typeP,
   UInt32 *creatorP,
   UInt16*numRecordsP
) 

Parameters

ref
The file reference returned from VFSFileOpen(). Note that the open file must be a .prc or .pdb file.
nameP
Pointer to a 32-byte character array in which the database name is returned. Pass NULL for this parameter if you do not want to retrieve the database name.
attributesP
Pointer to the database attributes stored in the file. The values returned are identical to the atttributes returned from DmDatabaseInfo(). See the Database Attribute Constants section for a description of each attribute. Pass NULL for this parameter if you do not want to retrieve the database's attributes.
versionP
Pointer to the application-specific version number of the database. The default version number is zero (0). Pass NULL for this parameter if you do not want to retrieve the version number.
crDateP
Pointer to the date the database was created, expressed in seconds since midnight (00:00:00) January 1, 1904. Pass NULL for this parameter if you do not want to retrieve the creation date.
modDateP
Pointer to the date the database was last modified, expressed in seconds since midnight (00:00:00) January 1, 1904. A database's modification date is updated only if a change has been made to the database when it is opened with write access. Pass NULL for this parameter if you do not want to retrieve the database's modification date.
bckUpDateP
Pointer to the date the database was last backed up, expressed in seconds since midnight (00:00:00) January 1, 1904. Pass NULL for this parameter if you do not want to retrieve the database's backup date.
modNumP
Pointer to the number of times the database was modified. This number is updated every time a record is added, modified, or deleted. Pass NULL for this parameter if you do not want to retrieve the modification count.
appInfoHP
Pointer to the application info block handle. If NULL is returned in this parameter, either there is no data in this field or an error occurred reading this data from the file. If a value other than NULL is returned, you must dispose of the allocated handle using MemHandleFree(). If you do not want to retrieve the application info block, pass NULL for this parameter
sortInfoHP
Pointer to the sort info block handle. If NULL is returned in this parameter, either there is no data in this field or an error occurred reading this data from the file. If a value other than NULL is returned, you must dispose of the allocated handle using MemHandleFree(). Pass NULL for this parameter if you do not want to retrieve the sort info block handle.
typeP
Pointer to the type of database as it was created. This may be a user-defined database type or a database type defined by the Palm OS. Some of the more common database types returned here are:

Type

Description

'appl'

Standard Palm application (resource database)

'libr'

Standard shared library

'libf'

File system shared library

'libs'

Slot driver shared library

'data'

Standard Palm data file (record database)

Pass NULL for this parameter if you do not want to retrieve the database's type.
creatorP
Pointer to the database's creator. Pass NULL for this parameter if you do not want to retrieve this information.
numRecordsP
Pointer to the number of records in the database. Pass NULL for this parameter if you do not want to retrieve this information.

Returns

Returns one of the following error codes:

errNone
No error
memErrNotEnoughSpace
There is not enough space in memory for the database header.
vfsErrBadData
The file referenced by the ref parameter is too small to contain a database header, or the database header is corrupted.

Comments

This function is analogous to DmDatabaseInfo(), but it works with files on an external card rather than with databases in main memory. See the Palm OS File Format Specification for a description of the header block in .prc and.pdb files.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSFileGetAttributes(), VFSFileGetDate()

VFSFileDelete Function ^TOP^

Purpose

Deletes a closed file or directory.

Declared In

VfsMgr.h

Prototype

Err VFSFileDelete(
   UInt16 volRefNum,
   constChar*pathNameP
)

Parameters

volRefNum
Volume reference number returned from VFSVolumeEnumerate().
pathNameP
Pointer to the full path of the file or directory to be deleted.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrBadName
The path name specified in pathNameP is not valid.
vfsErrDirNotEmpty
The directory being deleted is not empty.
vfsErrFileStillOpen
The file is still open.
vfsErrFileNotFound
The file could not be found.
vfsErrFilePermissionDenied
The requested permissions could not be granted.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.
vfsErrVolumeBadRef
The volume has not been mounted.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

VFSFileEOF Function ^TOP^

Purpose

Get end-of-file status for an open file. This function only operates on files and cannot be used with directories.

Declared In

VfsMgr.h

Prototype

Err VFSFileEOF (
   FileRef fileRef
)

Parameters

fileRef
File reference returned from VFSFileOpen().

Returns

Returns one of the following error codes:

errNone
No error. File pointer is not at end of the file.
vfsErrFileEOF
The file pointer is at the end of file.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrFileBadRef
The specified file reference is invalid.
vfsErrIsADirectory
The specified file reference points to a directory instead of a file. This is an invalid operation on a directory.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

VFSFileGetAttributes Function ^TOP^

Purpose

Obtain the attributes of an open file or directory.

Declared In

VfsMgr.h

Prototype

Err VFSFileGetAttributes (
   FileRef fileRef,
   UInt32*attributesP
)

Parameters

fileRef
File reference returned from VFSFileOpen().
attributesP
Pointer to the attributes associated with the file or directory. See File and Directory Attributes for a list of values that can be returned through this parameter.

Returns

Returns one of the following error codes:

errNone
No error
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrFileBadRef
The specified file reference is invalid.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSFileDBInfo(), VFSFileGetDate(), VFSFileSetAttributes()

VFSFileGetDate Function ^TOP^

Purpose

Obtain the dates on an open file or directory.

Declared In

VfsMgr.h

Prototype

Err VFSFileGetDate (
   FileRef fileRef,
   UInt16whichDate,
   UInt32 *dateP
)

Parameters

fileRef
File reference returned from VFSFileOpen().
whichDate
Specifies which date—creation, modification, or last access—you want. Supply one of the following values:
vfsFileDateCreated
vfsFileDateModified
vfsFileDateAccessed
Note that not all file systems are required to support the above dates. If the supplied date type is not supported by the file system, VFSFileGetDate returns expErrUnsupportedOperation.
dateP
Pointer to the requested date. This field is expressed in the standard Palm OS date format — the number of seconds since midnight (00:00:00) January 1, 1904.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
expErrUnsupportedOperation
The specified date type is not supported by the underlying file system.
vfsErrFileBadRef
The specified file reference is invalid.
sysErrParamErr
The whichDate parameter is not one of the defined constants.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSFileDBInfo(), VFSFileGetAttributes(), VFSFileSetDate()

VFSFileOpen Function ^TOP^

Purpose

Opens a file or directory and returns a reference for it.

Declared In

VfsMgr.h

Prototype

Err VFSFileOpen (
   UInt16 volRefNum,
   constChar*pathNameP,
   UInt16 openMode,
   FileRef*fileRefP
)

Parameters

volRefNum
The volume reference number returned from VFSVolumeEnumerate().
pathNameP
Pointer to the full path of the file or directory to be opened. This must be a valid path. It cannot be empty and can not contain null characters. The format of the pathname should match what the underlying file system supports. See "Naming Files" in Chapter 7, "Expansion," of the Palm OS Programmer's Companion, vol. I for a description of how to construct a valid path.
openMode
Mode to use when opening the file. See the Open Mode Constants section for a list of accepted modes.
fileRefP
Pointer to the opened file or directory reference which is supplied to various other VFSFile... operations. This value is filled in on return.

Returns

Returns one of the following error codes:

errNone
No error.
expErrCardReadOnly
The open mode requested includes write access but the file is read-only.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrBadName
The pathNameP parameter is invalid.
vfsErrFileNotFound
The specified file or directory could not be found.
vfsErrFilePermissionDenied
The file cannot be opened in the requested open mode, or it has already been opened with vfsModeExclusive.
vfsErrVolumeBadRef
The specified volume has not been mounted.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSFileClose(), VFSDirEntryEnumerate()

VFSFileRead Function ^TOP^

Purpose

Read data from a file into the dynamic heap. This function only operates on files and cannot be used with directories; use VFSDirEntryEnumerate() to explore the contents of a directory.

Declared In

VfsMgr.h

Prototype

Err VFSFileRead (
   FileRef fileRef,
   UInt32numBytes,
   void *bufP,
   UInt32*numBytesReadP
)

Parameters

fileRef
File reference returned from VFSFileOpen().
numBytes
Number of bytes to read.
bufP
Pointer to the destination chunk where the data is to be stored. This can be a pointer to any writable memory.
numBytesReadP
Pointer to an unsigned integer that reflects the number of bytes actually read. This value is set on return and does not need to be initialized. If no bytes are read the value is set to zero. Pass NULL for this parameter if you do not need to know how many bytes were read.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrFileBadRef
The specified file reference is invalid.
vfsErrFileEOF
The end of the file has been reached.
vfsErrFilePermissionDenied
Read permission is not enabled for this file.
vfsErrIsADirectory
The specified file reference is for a directory instead of a file. This is an invalid operation on a directory.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.

Comments

The file system does not use DmWrite() and cannot be used to read data into the storage heap.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSFileReadData(), VFSFileWrite(), VFSImportDatabaseFromFile()

VFSFileReadData Function ^TOP^

Purpose

Read data from a file into a chunk of memory in the storage heap. This function only operates on files and cannot be used with directories; use VFSDirEntryEnumerate() to explore the contents of a directory.

Declared In

VfsMgr.h

Prototype

Err VFSFileReadData (
   FileRef fileRef,
   UInt32numBytes,
   void *bufBaseP,
   UInt32 offset,
   UInt32 *numBytesReadP
)

Parameters

fileRef
File reference returned in VFSFileOpen().
numBytes
Number of bytes to read.
bufBaseP
Pointer to the destination chunk in the storage heap where the data is to be stored. This pointer must be obtained through the appropriate call to the Memory Manager API.
offset
Offset, in bytes, within the bufBaseP chunk where the data is to be written.
numBytesReadP
Pointer to an unsigned integer that reflects the number of bytes actually read. This value is set on return and does not need to be initialized. If no bytes are read, the value is set to zero. Pass NULL for this parameter if you do not need to know how many bytes were read.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrFileBadRef
The specified file reference is invalid.
vfsErrFileEOF
The end of the file has been reached.
vfsErrFilePermissionDenied
Read permission is not enabled for this file.
vfsErrIsADirectory
The specified file reference is for a directory instead of a file. This is an invalid operation on a directory.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.

Comments

When data is read from an external card with VFSFileReadData, it is copied into a chunk of memory in the storage heap. This chunk must be allocated by the application before the call to VFSFileReadData(). This function calls DmWrite() to put the data in the storage heap.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSFileRead(), VFSFileWrite()

VFSFileRename Function ^TOP^

Purpose

Rename a closed file or directory. This function cannot be used to move a file to another directory within the file system.

Declared In

VfsMgr.h

Prototype

Err VFSFileRename (
   UInt16 volRefNum,
   constChar*pathNameP,
   const Char *newNameP
)

Parameters

volRefNum
Volume reference number returned from VFSVolumeEnumerate().
pathNameP
Pointer to the full path of the file or directory to be renamed.
newNameP
Pointer to the new filename. Note that this is the name of the file only and does not include the path to the file.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrBadName
The name provided in either pathNameP or newNameP is invalid. This is also returned if the string pointed to by newNameP is a path, rather than a filename.
vfsErrFileAlreadyExists
A file with the new name already exists in this location.
vfsErrFileNotFound
The source file could not be found.
vfsErrFilePermissionDenied
Write permission is not enabled for this file.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.
vfsErrVolumeBadRef
The volume has not been mounted.
vfsErrVolumeFull
There is not enough space left on the volume.

Comments


WARNING! This function invalidates directory enumeration. You cannot continue enumerating files after renaming one of them with this function. If you need to operate on additional files in the directory, you must first restart the enumeration.

Example

Below is an example of how to use VFSFileRename. Note that the renamed file remains in the /PALM/Programs directory; VFSFileRename can't be used to move files from one directory to another.


// volRefNum must have been previously defined; most likely, 
// it was returned by VFSVolumeEnumerate 
 
err = VFSFileRename(volRefNum, "/PALM/Programs/foo.prc",
"bar.prc"); 
if (err != errNone) { 
// handle error... 
} 

Compatibility

Implemented only if the VFS Manager Feature Set is present.

VFSFileResize Function ^TOP^

Purpose

Change the size of an open file. This function only operates on files and cannot be used with directories.

Declared In

VfsMgr.h

Prototype

Err VFSFileResize (
   FileRef fileRef,
   UInt32newSize
)

Parameters

fileRef
File reference returned from VFSFileOpen().
newSize
The desired new size of the file. This can be larger or smaller then the current file size.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrFileBadRef
The specified file reference is invalid.
vfsErrIsADirectory
The specified file reference points to a directory instead of a file. This is an invalid operation on a directory.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.
vfsErrVolumeFull
There is not enough space left on the volume.

Comments

The location of the file pointer is undefined after a call to this function.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSFileSize()

VFSFileSeek Function ^TOP^

Purpose

Set the position within an open file from which to read or write. This function only operates on files and cannot be used with directories.

Declared In

VfsMgr.h

Prototype

Err VFSFileSeek (
   FileRef fileRef,
   FileOriginorigin,
   Int32 offset
)

Parameters

fileRef
File reference returned from VFSFileOpen().
origin
Origin to use when calculating the new position. The offset parameter indicates the desired new position relative to this origin, which can be one of the following:
vfsOriginBeginning
The beginning of the file.
vfsOriginCurrent
The current position within the file.
vfsOriginEnd
The end of the file. Only negative offsets are allowed when origin is set to vfsOriginEnd.
offset
Offset, either positive or negative, from the origin to which the current position should be set. A value of zero (0) positions you at the specified origin.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrFileBadRef
The specified file reference is invalid.
vfsErrFileEOF
The file pointer is at the end of file.
vfsErrIsADirectory
The specified file reference points to a directory instead of a file. This is an invalid operation on a directory.
sysErrParamErr
The specified origin is not one of the defined constants.

Comments

During a call to this function, if the resulting position would be beyond the end of the file, it sets the position to the end of the file.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSFileSize(), VFSFileTell()

VFSFileSetAttributes Function ^TOP^

Purpose

Change the attributes of an open file or directory.

Declared In

VfsMgr.h

Prototype

Err VFSFileSetAttributes (
   FileRef fileRef,
   UInt32attributes
)

Parameters

fileRef
File reference returned from VFSFileOpen().
attributes
Attributes to associate with the file or directory. See File and Directory Attributes for a list of values you can use when setting this parameter:

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
sysErrParamErr
One of the parameters is invalid.
vfsErrFileBadRef
The specified file reference is invalid.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.

Comments


NOTE: You cannot use this function to set the vfsFileAttrDirectory or vfsFileAttrVolumeLabel attributes. The vfsFileAttrDirectory is set when you call VFSDirCreate(). The vfsFileAttrVolumeLabel is set when you call VFSVolumeSetLabel(). This function may fail when setting other attributes, depending on the underlying file system.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSFileGetAttributes(), VFSFileSetDate()

VFSFileSetDate Function ^TOP^

Purpose

Changes the dates on an open file or directory.

Declared In

VfsMgr.h

Prototype

Err VFSFileSetDate (
   FileRef fileRef,
   UInt16whichDate,
   UInt32 date
)

Parameters

fileRef
File reference returned in VFSFileOpen().
whichDate
Specifies which date—creation, modification, or last access—to modify. Supply one of the following values:
vfsFileDateCreated
vfsFileDateModified
vfsFileDateAccessed
Note that not all file systems are required to support the above dates. If the supplied date type is not supported by the file system, VFSFileGetDate returns expErrUnsupportedOperation.
date
The new date. This field should be expressed in the standard Palm OS date format — the number of seconds since midnight (00:00:00) January 1, 1904.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
expErrUnsupportedOperation
The specified date type is not supported by the underlying file system.
sysErrParamErr
The whichDate parameter is not one of the defined constants.
vfsErrFileBadRef
The specified file reference is invalid.
vfsErrFilePermissionDenied
Write permission is not enabled for this file.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSFileGetDate(), VFSFileSetAttributes()

VFSFileSize Function ^TOP^

Purpose

Obtain the size of an open file. This function only operates on files and cannot be used with directories.

Declared In

VfsMgr.h

Prototype

Err VFSFileSize (
   FileRef fileRef,
   UInt32*fileSizeP
)

Parameters

fileRef
File reference returned from VFSFileOpen().
fileSizeP
Pointer to the size of the open file.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrFileBadRef
The specified file reference is invalid.
vfsErrIsADirectory
The specified file reference points to a directory instead of a file. This is an invalid operation on a directory.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSFileResize(), VFSFileTell(), VFSVolumeSize()

VFSFileTell Function ^TOP^

Purpose

Get the current position of the file pointer within an open file. This function only operates on files and cannot be used with directories.

Declared In

VfsMgr.h

Prototype

Err VFSFileTell (
   FileRef fileRef,
   UInt32*filePosP
)

Parameters

fileRef
File reference returned from VFSFileOpen().
filePosP
Pointer to the current file position.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrFileBadRef
The specified file reference is invalid.
vfsErrIsADirectory
The specified file reference points to a directory instead of a file. This is an invalid operation on a directory.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSFileSeek(), VFSFileSize()

VFSFileWrite Function ^TOP^

Purpose

Write data to an open file. This function only operates on files and cannot be used with directories.

Declared In

VfsMgr.h

Prototype

Err VFSFileWrite (
   FileRef fileRef,
   UInt32numBytes,
   const void *dataP,
   UInt32*numBytesWrittenP
)

Parameters

fileRef
File reference returned from VFSFileOpen().
numBytes
The number of bytes to write.
dataP
Pointer to the data that is to be written.
numBytesWrittenP
Pointer to an unsigned integer that reflects the number of bytes actually written. This value is set on return and does not need to be initialized. If no bytes are written the value is set to zero. Pass NULL for this parameter if you do not need to know how many bytes were written.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrFileBadRef
The specified file reference is invalid.
vfsErrFilePermissionDenied
Write permission is not enabled for this file.
vfsErrIsADirectory
The specified file reference points to a directory instead of a file. This is an invalid operation on a directory.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.
vfsErrVolumeFull
There is not enough space left on the volume.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSExportDatabaseToFile(), VFSExportDatabaseToFileCustom(), VFSFileRead(), VFSFileReadData()

VFSGetDefaultDirectory Function ^TOP^

Purpose

Determine the default location on the given volume for files of a particular type.

Declared In

VfsMgr.h

Prototype

Err VFSGetDefaultDirectory (
   UInt16 volRefNum,
   const Char *fileTypeStr,
   Char *pathStr,
   UInt16*bufLenP
)

Parameters

volRefNum
Volume reference number returned from VFSVolumeEnumerate().
fileTypeStr
Pointer to the requested file type, as a null-terminated string. The file type may either be a MIME media type/subtype pair, such as "image/jpeg", "text/plain", or "audio/basic"; or a file extension, such as ".jpeg."
pathStr
Pointer to the buffer which receives the default directory path for the requested file type.
bufLenP
Pointer to the size of the path. Set this to the size of pathStr buffer on input. Reflects the number of bytes copied to pathStr on output.

Returns

Returns one of the following error codes:

errNone
No error.
vfsErrBadName
There is no default directory registered for the requested file type.
vfsErrBufferOverflow
A match was found, but the pathStr buffer is too small to hold the resulting path string. A partial path is returned in pathStr.
vfsErrFileNotFound
No match was found for the specified volume. The error could have occurred with either the media type specified for this volume or the file type requested.

Comments

This function returns the complete path to the default directory registered for the specified file type. A default directory can be registered for each type of media supported. The directory should be registered under media and file type. Note that this directory is typically a "root" directory for the file type; any subdirectories under this root directory should also be searched for files of the appropriate type.

This function can be used by an image viewer application, for example, to find the directory containing images without having to know what type of media the volume was on. This could be
"/DCIM", "/images", or something else depending on the type of media.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSDirEntryEnumerate(), VFSRegisterDefaultDirectory(), VFSUnregisterDefaultDirectory()

VFSImportDatabaseFromFile Function ^TOP^

Purpose

Creates a database from a.pdb or.prc file on an external storage card.

Declared In

VfsMgr.h

Prototype

Err VFSImportDatabaseFromFile (
   UInt16volRefNum,
   const Char *pathNameP,
   UInt16 *cardNoP,
   LocalID*dbIDP
)

Parameters

volRefNum
Volume on which the source file resides.
pathNameP
Pointer to the full path and name of the source file.
cardNoP
Pointer to a variable that receives the card number of the newly-created database. If the database already resides in the storage heap, the card number of the existing database is returned along with the error dmErrAlreadyExists.
dbIDP
Pointer to a variable that receives the database ID of the new database. If the database already resides in the storage heap, the database ID of the existing database is returned along with the error dmErrAlreadyExists.

Returns

Returns one of the following error codes:

errNone
No error.
dmErrAlreadyExists
The.prc or.pdb file already exists in the storage heap. In this case the cardNoP and dbIDP are set to point to the existing file.
expErrNotEnoughPower
There is insufficient battery power to complete the requested operation.
vfsErrBadName
The path name specified in pathNameP is not valid.

Comments

This utility function imports a.pdb or.prc file resident on an external storage card into a new database in the storage heap. It first calls VFSFileOpen() to open the file specified in pathNameP. Assuming that a corresponding.prc or.pdb does not already exist in the storage heap, VFSImportDatabaseFromFile() calls the Exchange Manager function ExgDBRead() with an internal callback function for importing a file to the Data Manager. The Exchange Manager makes repeated calls to this function, which passes the data back in blocks. Once the file has been successfully imported, the owner (the imported file, if it's an executable, or the associated application if it is not) is sent a sysAppLaunchCmdSyncNotify launch code to make it aware of the new database.

This function only imports the specified.pdb or.prc file; it does not import bundled databases or overlays. If there are bundled databases and/or overlays associated with the.pdb or.prc file you are importing, you will need to write additional code to explicitly handle them.

This function doesn't provide any progress indication to the user. If you need to provide feedback to the user as the file import progresses, use VFSImportDatabaseFromFileCustom() instead.

This function is used, for example, to copy applications from a storage card to main memory.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSExportDatabaseToFile(), VFSFileRead()

VFSImportDatabaseFromFileCustom Function ^TOP^

Purpose

Create a database from the specified.pdb or.prc file on an external storage card. This function differs from VFSImportDatabaseFromFile() in that it allows you to track the progress of the import operation.

Declared In

VfsMgr.h

Prototype

Err VFSImportDatabaseFromFileCustom (
   UInt16volRefNum,
   const Char *pathNameP,
   UInt16*cardNoP,
   LocalID *dbIDP,
   VFSImportProcPtrimportProcP,
   void *userDataP
)

Parameters

volRefNum
Volume on which the source file resides.
pathNameP
Pointer to the full path and name of the source file.
cardNoP
Pointer to the variable that receives the card number of the newly-created database. If the database already resides in the storage heap, the card number of the existing database is returned along with the error dmErrAlreadyExists.
dbIDP
Pointer to the variable that receives the database ID of the new database. If the database already resides in the storage heap, the database ID of the existing database is returned along with the error dmErrAlreadyExists.
importProcP
User-defined callback function that tracks the progress of the import. This function should allow the user to cancel the import. Pass NULL if you don't have a progress callback function. See VFSImportProcPtr() for the requirements of this function.
userDataP
Pointer to any data you want to pass to the callback function specified in importProcP. This information is not used internally by the VFS Manager. Pass NULL if you don't have a progress callback function, or if that function doesn't need any such data.

Returns

Returns one of the following error codes:

errNone
No error
vfsErrBadName
The path name specified in pathNameP is not valid.
expErrNotEnoughPower
The power required to import a database is not available.
dmErrAlreadyExists
The.prc or.pdb file already exists in main memory. In this case the cardNoP and dbIDP are set to point to the existing file.

Comments

This function is similar to VFSImportDatabaseFromFile() in that it imports a.pdb or.prc file on an external storage card into a new database on the storage heap. It extends the functionality by allowing you to specify a callback function that tracks the progress of the export. It first calls VFSFileOpen() to open the file specified in pathNameP. If a corresponding.prc or .pdb does not already exist in main memory, it calls the Exchange Manager function ExgDBRead() with an internal callback function for importing the file from the Data Manager. The Exchange Manager makes repeated calls to this function, which receives the data back in blocks. The progress tracker, if one has been specified, is also called every time a new chunk of data is passed back. Once the file has been successfully imported, the owner (the imported file, if it's an executable, or the associated application if it is not) is sent a sysAppLaunchCmdSyncNotify launch code to make it aware of the new database.

Like VFSImportDatabaseFromFile, this function only imports the specified.pdb or.prc file; it does not import bundled databases or overlays.

This function is used, for example, to copy applications from a storage card to main memory.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSFileRead(), VFSExportDatabaseToFileCustom()

VFSInstallFSLib Function ^TOP^

Purpose

Install a file system library so that the VFS Manager can use it.

Declared In

VfsMgr.h

Prototype

Err VFSInstallFSLib (
   UInt32creator,
   UInt16*fsLibRefNumP
)

Parameters

creator
Creator ID of the database containing the file system library to be installed.
fsLibRefNumP
Pointer to the reference number for the newly installed file system library. Supply NULL for this parameter if you don't need the library reference number.

Returns

If the file system library was loaded and installed without error, errNone is returned. Any error generated by the underlying file system while opening the file system library or determining its type will be returned from VFSInstallFSLib. Other errors that can be generated during the file system library installation process include:

expErrIncompatibleAPIVer
The file system library has an incompatible API version.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
memErrNotEnoughSpace, memErrChunkNotLocked, or memErrChunkLocked
A memory problem occurred while inserting the library reference into the list of installed libraries.
sysErrLibNotFound, sysErrNoFreeRAM, sysErrNoFreeLibSlots (or some other error returned from the library's install entry point)
An error occurred while loading the library.

Comments

This function calls SysLibLoad() to load the file system library into the library table. Once loaded the appropriate file system is asked to open the library. At boot time VFSInstallFSLib is called internally by the Expansion Manager to load all installed file system libraries and initialize them for use.

VFSInstallFSLib is not normally called by applications.

Compatibility

Implemented only if the VFS Manager Feature Set is present. This function is not implemented, however, if Palm OS Cobalt Feature Set is present.

See Also

VFSRemoveFSLib()

VFSRegisterDefaultDirectory Function ^TOP^

Purpose

Registers a specific directory as the default location for files of a given type on a particular kind of external storage card. This function is generally called by a slot driver for files and media types that are supported by that slot driver.

Declared In

VfsMgr.h

Prototype

Err VFSRegisterDefaultDirectory (
   constChar*fileTypeStr,
   UInt32 mediaType,
   constChar *pathStr
)

Parameters

fileTypeStr
Pointer to the file type to register. This is a null-terminated string that can either be a MIME media type/subtype pair, such as "image/jpeg", "text/plain", or "audio/basic"; or a file extension, such as ".jpeg".
mediaType
Type of card media for which the default directory is being associated. See Defined Media Types in the Expansion Manager chapter for the list of accepted values.
pathStr
Pointer to the default directory path to be associated with the specified file type. This string must be null-terminated, and must be the full path to the directory.

Returns

Returns one of the following error codes:

errNone
No error.
sysErrParamErr
Either the fileTypeStr parameter is NULL or the pathStr parameter is NULL.
vfsErrFileAlreadyExists
A default directory has already been registered for this file type on the specified card media type.

Comments

This function first verifies that a default directory has not already been registered for the specified combination of file type and media type, and returns vfsErrFileAlreadyExists if one has been registered. To change an existing entry in the registry, you must first remove the existing entry with a call to VFSUnregisterDefaultDirectory() before re-registering it with VFSRegisterDefaultDirectory.

The specified directory registered for a given file type is intended to be the "root" default directory. If a given default directory has one or more subdirectories, applications should also search those subdirectories for files of the appropriate type.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSGetDefaultDirectory()

VFSRemoveFSLib Function ^TOP^

Purpose

Remove a file system library from the library table, so that the VFS Manager can no longer use it.

Declared In

VfsMgr.h

Prototype

Err VFSRemoveFSLib (
   UInt16fsLibRefNum
)

Parameters

fsLibRefNum
Library reference number of the file system library to remove from the library table.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrNoFileSystem
VFS Manager can not find the file system specified in fsLibRefNum.

Comments

This function is not normally called by applications. It unmounts any volumes that the specified file system may have mounted. It then closes the library and removes it from the library table with SysLibRemove().

Compatibility

Implemented only if the VFS Manager Feature Set is present. This function is not implemented, however, if Palm OS Cobalt Feature Set is present.

VFSUnregisterDefaultDirectory Function ^TOP^

Purpose

Sever the association between a particular file type and a default directory for a given type of card media.

Declared In

VfsMgr.h

Prototype

Err VFSUnregisterDefaultDirectory (
   constChar*fileTypeStr,
   UInt32mediaType
)

Parameters

fileTypeStr
Pointer to the file type with which the default directory is associated. This is a null-terminated string that can either be a MIME media type/subtype pair, such as "image/jpeg", "text/plain", or "audio/basic"; or a file extension, such as ".jpeg".
mediaType
Type of card media for which the default directory is associated. See Defined Media Types in the Expansion Manager chapter for the list of accepted values.

Returns

Returns one of the following error codes:

errNone
No error.
sysErrParamErr
The fileTypeStr parameter is NULL.
vfsErrFileNotFound
A default directory could not be found in the registry for the specified file and media type.

Comments


NOTE: Caution is advised when using this function, since you may remove another application's registration, causing data to mysteriously disappear from those applications.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSGetDefaultDirectory(), VFSRegisterDefaultDirectory()

VFSVolumeEnumerate Function ^TOP^

Purpose

Enumerate the mounted volumes.

Declared In

VfsMgr.h

Prototype

Err VFSVolumeEnumerate (
   UInt16 *volRefNumP,
   UInt32*volIteratorP
)

Parameters

volRefNumP
Pointer to the reference number for the volume represented by the current enumeration, or vfsInvalidVolRef if there are no more volumes to be enumerated or an error occurred.
volIteratorP
Pointer to a variable that holds the index of the current enumeration. Set the variable to vfsIteratorStart prior to the first iteration. Each call to VFSVolumeEnumerate updates the variable to the index of the next volume. When the last volume is reached, the variable pointed to by volIteratorP is set to vfsIteratorStop.

Returns

Returns one of the following error codes:

errNone
No error
expErrEnumerationEmpty
There are no volumes to enumerate.
sysErrParamErr
The value pointed to by volIteratorP is not valid. This error is also returned when volIteratorP is vfsIteratorStop.

Comments

This function returns a pointer to the volume reference number in the volRefNumP parameter. In order to traverse all volumes you must make repeated calls to VFSVolumeEnumerate() inside a loop. Before the first call to VFSVolumeEnumerate, the variable pointed to by volIteratorP should be initialized to vfsIteratorStart. Each iteration then increments volIteratorP to the next entry after updating volRefNumP. When the last volume is reached, *volIteratorP is set to vfsIteratorStop. If there are no volumes to enumerate, VFSVolumeEnumerate returns expErrEnumerationEmpty when first called.

Example

Below is an example of how to use VFSVolumeEnumerate.


UInt16 volRefNum; 
UInt32 volIterator = vfsIteratorStart; 
 
while (volIterator != vfsIteratorStop) { 
err = VFSVolumeEnumerate(&volRefNum, &volIterator);  
if (err == errNone) { 
// Do something with the volRefNum 
} else { 
// handle error... possibly by  
// breaking out of the loop 
} 
} 

Compatibility

Implemented only if the VFS Manager Feature Set is present.

VFSVolumeFormat Function ^TOP^

Purpose

Format and mount the volume installed in a given slot.

Declared In

VfsMgr.h

Prototype

Err VFSVolumeFormat (
   UInt8 flags,
   UInt16fsLibRefNum,
   VFSAnyMountParamPtrvfsMountParamP
)

Parameters

flags
Flags that control how the volume should be formatted. Currently, the only flag not reserved is vfsMountFlagsUseThisFileSystem. Pass this flag to cause the volume to be formatted using the file system specified by fsLibRefNum. Pass zero (0) to have the VFS Manager attempt to format the volume using a file system appropriate to the slot.
fsLibRefNum
Reference number of the file system library for which the volume should be formatted. This number is obtained through a call to SysLibFind() with the name of the library you want to use. If the flags field is not set to vfsMountFlagsUseThisFileSystem, this parameter is ignored.
vfsMountParamP
Parameters to be used when formatting the volume and when mounting the volume after it has been formatted. Supply a pointer to either a VFSSlotMountParamType or a VFSPOSEMountParamType structure. Note that you'll need to cast your structure pointer to a VFSAnyMountParamPtr. Set the mountClass field to the appropriate value: if you are mounting to an Expansion Manager slot, set mountClass to VFSMountClass_SlotDriver and initialize slotLibRefNum and slotRefNum to the appropriate values. See the descriptions of VFSAnyMountParamType, VFSSlotMountParamType, and VFSPOSEMountParamType for information on the fields that make up these data structures.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotEnoughPower
There is insufficient battery power to format and/or mount a volume.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.

Comments

The slot driver currently only supports one volume per slot. If the volume is successfully formatted and mounted, the reference number of the mounted volume is returned in vfsMountParamP->volRefNum. If the format is unsuccessful or cancelled, vfsMountParamP->volRefNum is set to vfsInvalidVolRef.

If vfsMountFlagsUseThisFileSystem is passed as a flag, VFSVolumeFormat attempts to format the volume using the file system library specified by fsLibRefNum. Typically the flag parameter is not set. In this case VFSVolumeFormat tries to find a compatible library to format the volume, as follows:

  1. Check to see if the default file system library feature is set. If it is, and if that file system is installed, it is used to format the volume. You can set the default file system using FtrSet(); supply sysFileCVFSMgr for the feature creator, and vfsFtrIDDefaultFS for the feature number.
  2. Check to see if any of the installed file systems are natively supported for the slot on which the VFS Manager is trying to format. If one of them is, it is used to format the volume.
  3. If none of the installed file systems can perform the format using the slot's native type, a dialog displays warning the user that their media may become incompatible with other devices if they continue with the format. The user may continue or cancel the format. If the user chooses to continue, VFSVolumeFormat formats the volume using the first file system library that was installed.

When calling VFSVolumeFormat, the volume can either be mounted or unmounted. The underlying file system library call requires the volume to be unmounted. VFSVolumeFormat checks to see if the volume is currently mounted and unmounts it, if necessary, using VFSVolumeUnmount before making the file system call. If the file system successfully formats the volume, VFSVolumeFormat mounts it and posts a sysNotifyVolumeMountedEvent notification.

Example

The following code excerpt formats a volume on an Expansion Manager slot using a compatible file system.


VFSSlotMountParamType slotParam; 
UInt32 slotIterator = expIteratorStart; 
 
slotParam.vfsMountParamP.mountClass = 
VFSMountClass_SlotDriver; 
err = ExpSlotEnumerate(&slotParam.slotRefNum, 
&slotIterator); 
err = ExpSlotLibFind(slotParam.slotRefNum,
&slotParam.slotLibRefNum); 
 
err = VFSVolumeFormat(NULL, NULL, 
(VFSAnyMountParamPtr) & slotParam); 

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSVolumeMount()

VFSVolumeGetLabel Function ^TOP^

Purpose

Determine the volume label for a particular volume.

Declared In

VfsMgr.h

Prototype

Err VFSVolumeGetLabel(
   UInt16 volRefNum,
   Char*labelP,
   UInt16 bufLen
)

Parameters

volRefNum
Volume reference number returned from VFSVolumeEnumerate().
labelP
Pointer to a character buffer into which the volume name is placed.
bufLen
Length, in bytes, of the labelP buffer.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.
vfsErrVolumeBadRef
The specified volume has not been mounted.
vfsErrBufferOverflow
The value specified in bufLen is not big enough to receive the full volume label.
vfsErrNameShortened
There was an error reading the full volume name. A shortened version is being returned.

Comments

Volume reference numbers can change each time you mount a given volume. To keep track of a particular volume, save the volume's label rather than its reference number. Volume labels can be up to 255 characters long. They can contain any normal character, including spaces and lower case characters, in any character set as well as the following special characters: $ % ' - _ @ ~ ` ! ( ) ^ # & + , ; = [ ].

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSVolumeSetLabel()

VFSVolumeInfo Function ^TOP^

Purpose

Get information about the specified volume.

Declared In

VfsMgr.h

Prototype

Err VFSVolumeInfo(
   UInt16 volRefNum,
   VolumeInfoType *volInfoP
)

Parameters

volRefNum
Volume reference number returned from VFSVolumeEnumerate().
volInfoP
Pointer to the structure that receives the volume information for the specified volume. See VolumeInfoType for more information on the fields in this data structure.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.
vfsErrVolumeBadRef
The specified volume reference number is invalid.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSVolumeGetLabel(), VFSVolumeSize()

VFSVolumeMount Function ^TOP^

Purpose

Mount the card's volume on the specified slot.

Declared In

VfsMgr.h

Prototype

Err VFSVolumeMount(
   UInt8 flags,
   UInt16fsLibRefNum,
   VFSAnyMountParamPtrvfsMountParamP
)

Parameters

flags
Flags that control how the volume should be mounted. Currently, the only flag not reserved is vfsMountFlagsUseThisFileSystem. Pass this flag to cause the volume to be mounted using the file system specified by fsLibRefNum. Pass zero (0) to have the VFS Manager attempt to mount the volume using a file system appropriate for the slot.
fsLibRefNum
Reference number of the file system library for which the volume should be mounted. This number is obtained through a call to SysLibFind() with the name of the library you want to use. If the flags field is not set to vfsMountFlagsUseThisFileSystem, this parameter is ignored.
vfsMountParamP
Parameters to be used when mounting the volume after it has been formatted. Supply a pointer to either a VFSSlotMountParamType or a VFSPOSEMountParamType structure. Note that you'll need to cast your structure pointer to a VFSAnyMountParamPtr. Set the mountClass field to the appropriate value: if you are mounting to an Expansion Manager slot, set mountClass to VFSMountClass_SlotDriver and initialize slotLibRefNum and slotRefNum to the appropriate values. See the descriptions of VFSAnyMountParamType, VFSSlotMountParamType, and VFSPOSEMountParamType for information on the fields that make up these data structures.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotEnoughPower
There is insufficient battery power to mount a volume.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
sysErrParamErr
vfsMountParamP was initialized to NULL.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.
vfsErrVolumeStillMounted
The volume is already mounted with a different file system than was specified in fsLibRefNum.

Comments

The slot driver only supports one volume per slot. The reference number of the mounted volume is returned in vfsMountParamP->volRefNum. If vfsMountFlagsUseThisFileSystem is passed as a flag, VFSVolumeMount attempts to mount the volume using the file system library specified by fsLibRefNum. Otherwise VFSVolumeMount tries to find a file system library which is able to mount the volume. If none of the installed file system libraries is able to mount the volume, VFSVolumeMount attempts to re-format the volume (using VFSVolumeFormat()) and then mount it. If VFSVolumeMount manages to successfully mount the volume, it ends by posting a sysNotifyVolumeMountedEvent notification.

After VFSVolumeMount successfully mounts a volume, it broadcasts sysNotifyVolumeMountedEvent. The VFS Manager, upon being notified of this event, searches the newly-mounted volume for /PALM/start.prc. If start.prc is found in the /PALM directory, the VFS Manager copies it to main memory and launches it. If start.prc is not found, the VFS Manager switches to the Launcher instead. This behavior can be overridden; see Card Insertion and Removal in Chapter 7, "Expansion," Palm OS Programmer's Companion, vol. I.

When VFSVolumeMount is called, if the volume is already mounted with a different file system than was specified in fsLibRefNum, a vfsErrVolumeStillMounted error is returned. If the volume is already mounted with the same file system that is specified in fsLibRefNum, or if vfsMountFlagsUseThisFileSystem is not set, VFSVolumeMount returns errNone and sets volRefNumP to the reference number of the currently mounted volume.

Example

The following code excerpt mounts a volume on an Expansion Manager slot using a compatible file system.


VFSSlotMountParamType slotParam ; 
UInt32 slotIterator = expIteratorStart; 
 
slotParam.vfsMountParamP.mountClass = 
VFSMountClass_SlotDriver; 
err = ExpSlotEnumerate(&slotParam.slotRefNum, 
&slotIterator); 
err = ExpSlotLibFind(slotParam.slotRefNum, 
&slotParam.slotLibRefNum); 
 
err = VFSVolumeMount(NULL, NULL,
(VFSAnyMountParamPtr) & slotParam); 

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSVolumeFormat(), VFSVolumeUnmount()

VFSVolumeSetLabel Function ^TOP^

Purpose

Changes the volume label for a mounted volume.

Declared In

VfsMgr.h

Prototype

Err VFSVolumeSetLabel(
   UInt16 volRefNum,
   constChar*labelP
)

Parameters

volRefNum
Volume reference number returned from VFSVolumeEnumerate().
labelP
Pointer to the label to be applied to the specified volume. This string must be null-terminated.

Returns

Returns one of the following error codes:

errNone
No error
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrBadName
The supplied label is invalid.
vfsErrNameShortened
Indicates that the label name was too long. A shortened version of the label name was used instead.
vfsErrVolumeBadRef
The specified volume has not been mounted.

Comments

Volume labels can be up to 255 characters long. They can contain any normal character, including spaces and lower case characters, in any character set as well as the following special characters: $ % ' - _ @ ~ ` ! ( ) ^ # & + , ; = [ ]. See Naming Volumes in Chapter 7, "Expansion,"Palm OS Programmer's Companion, vol. I for guidelines on naming.


NOTE: Most clients should not need to call this function. This function may create or delete a file in the root directory, which would invalidate any current calls to VFSDirEntryEnumerate().

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSVolumeGetLabel()

VFSVolumeSize Function ^TOP^

Purpose

Determine the total amount of space on a volume, as well as the amount that is currently being used.

Declared In

VfsMgr.h

Prototype

Err VFSVolumeSize(
   UInt16 volRefNum,
   UInt32*volumeUsedP,
   UInt32 *volumeTotalP
)

Parameters

volRefNum
Volume reference number returned from VFSVolumeEnumerate().
volumeUsedP
Pointer to a variable that receives the amount of space, in bytes, in use on the volume.
volumeTotalP
Pointer to a variable that receives the total amount of space on the volume, in bytes.

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.
vfsErrVolumeBadRef
The specified volume has not been mounted.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSVolumeInfo()

VFSVolumeUnmount Function ^TOP^

Purpose

Unmount the given volume.

Declared In

VfsMgr.h

Prototype

Err VFSVolumeUnmount(
   UInt16 volRefNum
)

Parameters

volRefNum
Volume reference number returned from VFSVolumeEnumerate().

Returns

Returns one of the following error codes:

errNone
No error.
expErrNotOpen
The file system library necessary for this call has not been installed or has not been opened.
vfsErrNoFileSystem
The VFS Manager cannot find an appropriate file system to handle the request.
vfsErrVolumeBadRef
The specified volume has not been mounted.

Comments

This function closes any opened files and posts a sysNotifyVolumeUnmountedEvent notification once the file system is successfully unmounted.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSVolumeMount()

Application-Defined Functions ^TOP^

VFSExportProcPtr Function ^TOP^

Purpose

User-defined callback function supplied to VFSExportDatabaseToFileCustom() that tracks the progress of the export.

Declared In

VfsMgr.h

Prototype

typedef Err (
   *VFSExportProcPtr
) (
   UInt32totalBytes,
   UInt32 offset,
   void*userDataP
)

Parameters

totalBytes
The total number of bytes being exported.
offset
Undefined.
userDataP
Pointer to any application-specific data passed to the callback function. This pointer may be NULL if your callback doesn't need any such data.

Returns

Your progress tracker should allow the user to abort the export. Return errNone if the export should continue, or any other value to abort the export process. If you return a value other than errNone, that value will be returned by VFSExportDatabaseToFileCustom().

Comments

See the Progress Dialogs section in the Palm OS Programmer's Companion, vol. I for more information on writing a progress tracker.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSImportProcPtr()

VFSImportProcPtr Function ^TOP^

Purpose

User-defined callback function supplied to VFSImportDatabaseFromFileCustom() that tracks the progress of the import.

Declared In

VfsMgr.h

Prototype

typedef Err (
   *VFSImportProcPtr
) (
   UInt32totalBytes,
   UInt32 offset,
   void*userDataP
)

Parameters

totalBytes
The total number of bytes being imported.
offset
The number of bytes that have already been imported. This value, along with the total number of bytes being imported, allows you to inform the user how far along the import is.
userDataP
Pointer to NY application-specific data passed to the callback function. This pointer may be NULL if your callback doesn't need any such data.

Returns

Your progress tracker should allow the user to abort the import. Return errNone if the import should continue, or any other value to abort the import process. If you return a value other than errNone, that value will be returned by VFSImportDatabaseFromFileCustom().

Comments

See the Progress Dialogs section in the Palm OS Programmer's Companion, vol. I for more information on writing a progress tracker.

Compatibility

Implemented only if the VFS Manager Feature Set is present.

See Also

VFSExportProcPtr()