DosSetFileSizeL
Description
DosSetFileSizeL changes the size of a file.
Syntax
#define INCL DOSFILEMGR #include os2.h APIRET DosSetFileSizeL (HFILE hFile, LONGLONG cbSize)
Parameters
- hFile HFILE) input
- The handle of the file whose size to be changed.
- cbSize LONGLONG) input
- The new size, in bytes, of the file.
Return Code
ulrc APIRET) returns
DosSetFileSizeL returns one of the following values:
- 0 NO_ERROR
- ERROR_ACCESS_DENIED
- ERROR_INVALID_HANDLE
- 26 ERROR_NOT_DOS_DISK
- 33 ERROR_LOCK_VIOLATION
- 87 ERROR_INVALID_PARAMETER
- 112 ERROR_DISK_FULL
Remarks
When DosSetFileSizeL is issued, the file must be open in a mode that allows write access.
The size of the open file can be truncated or extended. If the file size is being extended, the file system tries to allocate additional bytes in a contiguous (or nearly contiguous) space on the medium. The values of the new bytes are undefined.
Example Code
This example writes to a file named DOSMAN.DAT, resets the buffer, and changes the file size.
#define INCL_DOSFILEMGR /* File Manager values */
#define INCL_DOSERRORS /* DOS Error values */
#include os2.h
#include stdio.h
#include string.h
int main(VOID)
HFILE hfFileHandle = 0L; /* Handle for file being manipulated */
ULONG ulAction = 0; /* Action taken by DosOpenL */
ULONG ulWrote = 0; /* Number of bytes written by DosWrite */
UCHAR uchFileName 20 = "dosman.dat", /* Name of file */
uchFileData 4 = "DATA"; /* Data to write to file */
APIRET rc = NO_ERROR; /* Return code */
/* Open the file dosman.dat. Use an existing file or create a new */
/* one if it doesn't exist. */
rc = DosOpenL(uchFileName, hfFileHandle, ulAction, (LONGLONG)4,
FILE_ARCHIVED | FILE_NORMAL,
OPEN_ACTION_CREATE_IF_NEW | OPEN_ACTION_OPEN_IF_EXISTS,
OPEN_FLAGS_NOINHERIT | OPEN_SHARE_DENYNONE |
OPEN_ACCESS_READWRITE, 0L);
if (rc != NO_ERROR)
printf("DosOpenL error return code = %u\n", rc);
return 1;
rc = DosWrite (hfFileHandle, (PVOID) uchFileData,
sizeof (uchFileData), ulWrote);
if (rc != NO_ERROR)
printf("DosWrite error return code = %u\n", rc);
return 1;
rc = DosResetBuffer (hfFileHandle);
if (rc != NO_ERROR)
printf("DosResetBuffer error return code = %u\n", rc);
return 1;
/* endif */
rc = DosSetFileSizeL (hfFileHandle, (LONGLONG)8); /* Change file size */
if (rc != NO_ERROR)
printf("DosSetFileSizeL error return code = %u\n", rc);
return 1;
return NO_ERROR;