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DosClose
This call closes a handle to a file, pipe, or device.
Syntax
DosClose (FileHandle)
Parameters
;FileHandle (HFILE) - input : Handle returned by a previous DosOpen, DosMakeNmPipe, or DosMakePipe call.
Return Code
rc (USHORT) - return Return code descriptions are: * 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 one or more additional handles to a file have been created with DosDupHandle, the directory is not updated and all internal buffers are not written to the medium until DosClose has been issued for the duplicated handles.
Closing a handle to a device causes the device to be notified of the close, if appropriate.
Named Pipe Considerations
DosClose closes a named pipe by handle. When all handles referencing one end of a pipe are closed, the pipe is considered broken.
If the client end closes, no other process can re-open the pipe until the serving end issues a DosDisConnectNmPipe followed by a DosConnectNmPipe.
If the server end closes when the pipe is already broken, it is deallocated immediately; otherwise, the pipe is not deallocated until the last client handle is closed.
Example Code
C Binding
<PRE> #define INCL_DOSFILEMGR
USHORT rc = DosClose(FileHandle);
HFILE FileHandle; /* File handle */ USHORT rc; /* return code */ </PRE> This example opens a file, then closes it. <PRE> #define INCL_DOSFILEMGR
#define OPEN_FILE 0x01 #define CREATE_FILE 0x10 #define FILE_ARCHIVE 0x20 #define FILE_EXISTS OPEN_FILE #define FILE_NOEXISTS CREATE_FILE #define DASD_FLAG 0 #define INHERIT 0x80 #define WRITE_THRU 0 #define FAIL_FLAG 0 #define SHARE_FLAG 0x10 #define ACCESS_FLAG 0x02
#define FILE_NAME “test.dat” #define FILE_SIZE 800L #define FILE_ATTRIBUTE FILE_ARCHIVE #define RESERVED 0L
HFILE FileHandle; USHORT Wrote; USHORT Action; PSZ FileData[100]; USHORT rc;
Action = 2;
strcpy(FileData, "Data...");
if(!DosOpen(FILE_NAME, /* File path name */
&FileHandle, /* File handle */
&Action, /* Action taken */
FILE_SIZE, /* File primary allocation */
FILE_ATTRIBUTE, /* File attribute */
FILE_EXISTS | FILE_NOEXISTS, /* Open function type */
DASD_FLAG | INHERIT | /* Open mode of the file */
WRITE_THRU | FAIL_FLAG |
SHARE_FLAG | ACCESS_FLAG,
RESERVED)) /* Reserved (must be zero) */
rc = DosClose(FileHandle); /* File Handle */
</PRE>
MASM Binding
<PRE> EXTRN DosClose:FAR INCL_DOSFILEMGR EQU 1
PUSH WORD FileHandle ;File handle CALL DosClose
Returns WORD </PRE>
Note
Text based on http://www.edm2.com/index.php/DosClose_(FAPI)