DosProtectClose

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Description

Closes a handle to a file, pipe, or device.

Syntax

#define INCL_DOSFILEMGR
#include <os2.h>

HFILE     hFile;               /*  The handle returned by a previous call to a DosProtectOpen. */
FHLOCK    fhFileHandleLockID;  /*  The filehandle lockid obtained from DosProtectOpen. */
APIRET    ulrc;                /*  Return Code. */

ulrc = DosProtectClose(hFile, fhFileHandleLockID);

Parameters

hFile (HFILE) - input 
The handle returned by a previous call to a DosProtectOpen.
fhFileHandleLockID (FHLOCK) - input 
The filehandle lockid obtained from DosProtectOpen.

Return Code

ulrc (APIRET) - returns

DosProtectClose returns one of the following values:

  • 0 NO_ERROR
  • 2 ERROR_FILE_NOT_FOUND
  • 5 ERROR_ACCESS_DENIED
  • 6 ERROR_INVALID_HANDLE

Remarks

Issuing DosProtectClose with the handle to a file closes a handle to a file, pipe, or device.

Closing a device handle causes the device to be notified of the close, if appropriate.

Named-Pipe Considerations

DosProtectClose closes a named pipe by handle. When all handles that refer to one end of a pipe are closed, the pipe is considered broken.

If the client end closes, no other process can reopen the pipe until the serving end issues DosDisConnectNPipe, followed by DosConnectNPipe.

If the server end closes when the pipe is already broken, the pipe is immediately deallocated; otherwise, it is not deallocated until the last client handle is closed.

Example Code

This example opens or creates and opens a file named "DOSPROT.DAT", writes to it, reads from it, and finally closes it 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;
   ULONG  ulAction       = 0;
   ULONG  ulBytesRead    = 0;
   ULONG  ulWrote        = 0;
   ULONG  ulLocal        = 0;
   UCHAR  uchFileName[20]  = "dosprot.dat",
          uchFileData[100] = " ";
   FHLOCK FileHandleLock = 0;        /* File handle lock   */
   APIRET rc             = NO_ERROR; /* Return code */

   /* Open the file dosprot.dat.  Make it read/write, open it */
   /* if it already exists and create it if it is new.     */
   rc = DosProtectOpen(uchFileName,             /* File path name          */
                &hfFileHandle,                  /* File handle             */
                &ulAction,                      /* Action taken            */
                100L,                           /* File primary allocation */
                FILE_ARCHIVED | FILE_NORMAL,    /* File attribute          */
                OPEN_ACTION_CREATE_IF_NEW |
                OPEN_ACTION_OPEN_IF_EXISTS,     /* Open function type      */
                OPEN_FLAGS_NOINHERIT |
                OPEN_SHARE_DENYNONE  |
                OPEN_ACCESS_READWRITE,          /* Open mode of the file   */
                0L,                             /* No extended attribute   */
                &FileHandleLock);               /* File handle lock id     */
   if (rc != NO_ERROR) {
      printf("DosProtectOpen error: return code = %u\n", rc);
      return 1;
   } else {
     printf ("DosProtectOpen: Action taken = %u\n", ulAction);
   } /* endif */

   /* Write a string to the file */
   strcpy (uchFileData, "testing...\n3...\n2...\n1\n");
   rc = DosProtectWrite (hfFileHandle,       /* File handle                  */
                  (PVOID) uchFileData,       /* String to be written         */
                  sizeof (uchFileData),      /* Size of string to be written */
                  &ulWrote,                  /* Bytes actually written       */
                  FileHandleLock);           /* File handle lock id          */
   if (rc != NO_ERROR) {
      printf("DosProtectWrite error: return code = %u\n", rc);
      return 1;
   } else {
      printf ("DosProtectWrite: Bytes written = %u\n", ulWrote);
   } /* endif */

   /* Move the file pointer back to the beginning of the file */
   rc = DosProtectSetFilePtr (hfFileHandle,    /* File Handle          */
                       0L,                     /* Offset               */
                       FILE_BEGIN,             /* Move from BOF        */
                       &ulLocal,               /* New location address */
                       FileHandleLock);        /* File handle lock id  */
   if (rc != NO_ERROR) {
      printf("DosSetFilePtr error: return code = %u\n", rc);
      return 1;
   }

   /* Read the first 100 bytes of the file */
   rc = DosProtectRead (hfFileHandle,         /* File Handle                 */
                 uchFileData,                 /* String to be read           */
                 100L,                        /* Length of string to be read */
                 &ulBytesRead,                /* Bytes actually read         */
                 FileHandleLock);             /* File handle lock id         */
   if (rc != NO_ERROR) {
      printf("DosProtectRead error: return code = %u\n", rc);
      return 1;
   } else {
      printf("DosProtectRead: Bytes read = %u\n%s\n", ulBytesRead, uchFileData);
   } /* endif */

   rc = DosProtectClose(hfFileHandle, FileHandleLock);   /* Close the file */
   if (rc != NO_ERROR) {
      printf("DosProtectClose error: return code = %u\n", rc);
      return 1;
    }
   return NO_ERROR;
}

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