This function retrieves the size, in bytes, of the specified file that resides in an installable file system. The application does not call this function directly. Instead, use the corresponding standard Win32 function GetFileSize. The file system driver (FSD) Manager determines the file system type and calls the MyFSD_GetFileSize implementation of the function.
At a Glance
| Header file: | Fsdmgr.h |
| Windows CE versions: | 2.10 and later |
Syntax
DWORD MyFSD_GetFileSize( PFILE pFile, PDWORD pFileSizeHigh);
Parameters
pFile
Pointer to the value that the file system driver (FSD) passes to the FSDMGR_CreateFileHandle function when creating the file handle.
pFileSizeHigh
Pointer to the variable where the high-order word of the file size is returned. This parameter can be NULL if the application does not require the high-order word.
Return Values
If the function succeeds, the return value is the low-order doubleword of the file size, and, if lpFileSizeHigh is non-NULL, the function puts the high-order doubleword of the file size into the variable pointed to by that parameter.
If the function fails and lpFileSizeHigh is NULL, the return value is 0xFFFFFFFF. To get extended error information, call GetLastError.
If the function fails and lpFileSizeHigh is non-NULL, the return value is 0xFFFFFFFF and GetLastError returns a value other than NO_ERROR.
Remarks
The GetFileSize function obtains the uncompressed size of a file.
An FSD exports this function if it wants to support the GetFileSize function. All FSD functions can be called reentryly, therefore, FSD developers must take this into account when developing an FSD.
The Fsdmgr component is a dynamic-link library (DLL) that manages all operating system interaction with installable files systems. Each installable file system requires an FSD, which is a DLL that exports an API needed to support an installable file system. The name of the DLL for the FSD and the names of the functions it exports start with the name of the associated installable file system. For example, if the name of file system is MyFSD, then its DLL is MyFSD.dll and its exported functions are prefaced with MyFSD_*.
Fsdmgr provides service functions to FSDs. The FSDMGR_RegisterVolume, FSDMGR_CreateFileHandle, and FSDMGR_CreateSearchHandle functions record a DWORD of volume-specific data the FSD needs to keep associated with volume. This volume-specific data is passed as the first parameter of these three functions.
Applications that access an installable file system use standard Win32 functions. For example, when an application wants to create a folder on a device that contains an installable file system, it calls CreateDirectory. Fsdmgr recognizes that the path is to a device containing an installable file system and calls the appropriate function, which in the case of the MyFSD file system is MyFSD_CreateDirectoryW. That is, the application calls CreateDirectory, causing Fsdmgr to call MyFSD_CreateDirectoryW.
See Also