Create DOS File

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Revision as of 09:32, 13 June 2009

Create DOS File Syntax: DOSFC(AX-value, CX-value, file-name) EXCP=statement-label Entry: AX-value = "@3C00@"

 CX-value = "@0000@"

Return: If the function call is successful, the AX field will contain the

 file's handle.

 If an exception occurs, byte 2 of the AX field will contain the
 DOS error code (in hex).

Discussion: The DOSFC function call can be used to create a DOS file. This call requires that the AX-value be set to "@3C00@", the CX-value to null, and the file-name to the name of the DOS file to be created (including disk and path name). After the call is executed, the AX field will contain the file's handle. It is imperative that this value be stored for future use (i.e., for closing the file).

Example:  ! S SFCREATE,DSK

 ! O FCREATE,DSK
 ! L T00,E
 ! R QMONITOR
 !
 !==========  CREATE DOS FILE  ===================================
 !
 LENGTH 2 & LOCAL AX$,CX$                ! Define registers
 LENGTH 2 & LOCAL FILEHANDLE$            ! Define file handle
 LENGTH 64 & LOCAL FILENAME$             ! Define file name
 !
 LENGTH  3 & LOCAL DOSCODE$              ! Define DOS error code
 LENGTH 37 & LOCAL DOSMESSAGE$           ! Define DOS message
 !
 1000 FORMAT DOSMESSAGE$                 ! File input format
 !
 100 FORMAT (ET)                         ! Screen format
 !
 CLEAR                                   ! Initialize variables
 PRINT (0,100)                           ! Set typewriter mode
 !
 PRINT (0) "ENTER FILENAME:"             ! Display prompt
 INPUT (0) FILENAME$                     ! Enter file name
 IF FILENAME$ = "" THEN RUN "QMONITOR"   ! If null, then stop
 FILENAME$ = FILENAME$ + "@00@"          ! Add null byte to name
 !
 AX$ = "@3C00@"                          ! Set AX to "CREATE FILE"
 CX$ = "@0000@"                          ! Set CX register to null
 !
 DOSFC(AX$,CX$,FILENAME$) EXCP=EXCEPTION ! Perform DOSFC call
 !
 FILEHANDLE$ = AX$                       ! Save file handle
 !
 PRINT (0) FILENAME$;" CREATED SUCCESSFULLY."
 PRINT (0) "FILE HANDLE IS:";FILEHANDLE$
 INPUT (0) ""
 RUN "QMONITOR"
 !
 EXCEPTION:                              ! Exception routine
 PRINT (0) "FILE NOT CREATED."           ! Display message
 OPEN (1) "QERCOMET"                     ! Open error file
 DOSCODE$ = "D" + HEXASC(SUB(AX$,2,1))   ! Construct key to file
 READ (1,1000) KEY=DOSCODE$              ! Read error record
 PRINT (0) "DOS error code: ";DOSCODE$   ! Display DOS error code
 PRINT (0) DOSMESSAGE$                   ! Display error message
 INPUT (0) ""                            ! Hold
 CLOSE (1)                               ! Close error file
 RUN "QMONITOR"                          ! Exit
 END