DosClose

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

Syntax
DosClose (hFile)

Parameters

 * hFile (HFILE) - input: The handle returned by a previous call to DosCreateNPipe, DosCreatePipe, DosDupHandle, or DosOpen.

Return Code

 * ulrc (APIRET) - returns:DosClose returns one of the following values:
 * 0 NO_ERROR
 * 2 ERROR_FILE_NOT_FOUND
 * 5 ERROR_ACCESS_DENIED
 * 6 ERROR_INVALID_HANDLE

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

If additional handles to a file were created with DosDupHandle, DosClose must be issued for the duplicate handles before the directory is updated, and information in internal buffers is written to the medium.

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

Named-Pipe Considerations
DosClose 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 "DOSTEST.DAT", writes to it, reads from it, and finally closes it. 
 * 1) define INCL_DOSFILEMGR         /* File Manager values */
 * 2) define INCL_DOSERRORS          /* DOS Error values    */
 * 3) include 
 * 4) include 
 * 5) include 

int main(void) { HFILE hfFileHandle   = 0L;  /* Handle for file being manipulated */ ULONG ulAction       = 0;   /* Action taken by DosOpen */ ULONG ulBytesRead    = 0;   /* Number of bytes read by DosRead */ ULONG ulWrote        = 0;   /* Number of bytes written by DosWrite */ ULONG ulLocal        = 0;   /* File pointer position after DosSetFilePtr */ UCHAR uchFileName[20]  = "dostest.dat",  /* Name of file */ uchFileData[100] = " ";           /* Data to write to file */ APIRET rc            = NO_ERROR;         /* Return code */

/* Open the file dostest.dat. Use an existing file or create a new */ /* one if it doesn't exist. */  rc = DosOpen(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 */

if (rc != NO_ERROR) { printf("DosOpen error: return code = %u\n", rc); return 1; } else { printf ("DosOpen: Action taken = %ld\n", ulAction); } /* endif */

/* Write a string to the file */ strcpy (uchFileData, "testing...\n1...\n2...\n3\n"); rc = DosWrite (hfFileHandle,             /* File handle */                  (PVOID) uchFileData,       /* String to be written */                  sizeof (uchFileData),      /* Size of string to be written */                  &ulWrote);                 /* Bytes actually written */

if (rc != NO_ERROR) { printf("DosWrite error: return code = %u\n", rc); return 1; } else { printf ("DosWrite: Bytes written = %u\n", ulWrote); } /* endif */

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

/* Read the first 100 bytes of the file */ rc = DosRead (hfFileHandle,               /* File Handle */                 uchFileData,                 /* String to be read */                 100L,                        /* Length of string to be read */                 &ulBytesRead);               /* Bytes actually read */

if (rc != NO_ERROR) { printf("DosRead error: return code = %u\n", rc); return 1; } else { printf ("DosRead: Bytes read = %u\n%s\n", ulBytesRead, uchFileData); } /* endif */

rc = DosClose(hfFileHandle);               /* Close the file */

if (rc != NO_ERROR) { printf("DosClose error: return code = %u\n", rc); return 1; }  return NO_ERROR; } 

Related Functions

 * DosConnectNPipe
 * DosCreateNPipe
 * DosDisConnectNPipe
 * DosDupHandle
 * DosOpen
 * DosResetBuffer