Purpose

DosProtectSetFileSizeL changes the size of a file.

Syntax

#define INCL DOSFILEMGR
#include  os2.h 

APIRET DosProtectSetFileSizeL

(HFILE hFile, LONGLONG cbSize, FHLOCK fhFileHandleLockID)

Parameters

hFile HFILE) input

Handle of the file whose size to be changed.
cbSize LONGLONG) input
New size, in bytes, of the file.
fhFileHandleLockID FHLOCK) input
The filehandle lockid obtained from DosProtectOpenL.

Returns

ulrc APIRET) returns

Return Code.

DosProtectSetFileSizeL returns one of the following values

• 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 DosProtectSetFileSizeL 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.

  Related Functions

  • DosProtectOpenL

  • DosProtectQueryFileInfo

  • DosQueryPathInfo

  Example Code

  This example writes to a file named DOSPMAN.DAT , resets the buffer, and changes the size of the file using DosProtect functions.

  #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 */
  FHLOCK FileHandleLock = 0;      /* File handle lock   */
  
  ULONG  ulWrote        = 0;      /* Number of bytes written by DosWrite */
  UCHAR  uchFileName 20   = "dospman.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 = DosProtectOpenL(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,  FileHandleLock);
  if (rc != NO_ERROR)  
  printf("DosProtectOpenL error  return code = %u\n", rc);
  return 1;
   
  
  rc = DosProtectWrite (hfFileHandle, (PVOID) uchFileData,
  sizeof (uchFileData),  ulWrote, FileHandleLock);
  if (rc != NO_ERROR)  
  printf("DosProtectWrite 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 = DosProtectSetFileSizeL (hfFileHandle, (LONGLONG)8, FileHandleLock);
  if (rc != NO_ERROR)  
  printf("DosProtectSetFileSizeL error  return code = %u\n", rc);
  return 1;
   
  
  return NO_ERROR;
   
  

  ---

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