Badge at 09:51, 13 June 2009

2009-06-13T09:51:36Z

← Older revision		Revision as of 09:51, 13 June 2009
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-	'''Return:''' If the function call is successful, the AX field will contain the	+	'''Return:''' <br>
-	file's handle.	+	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	+	If an exception occurs, byte 2 of the AX field will contain the DOS error code (in hex).
-	DOS error code (in hex).	+

Badge: New page: '''Open DOS File''' '''Syntax:'''
DOSFC(AX-value, CX-value, file-name) EXCP=statement-label '''Entry:''' AX-value = "@3D00@" (read only) CX-value = "@0000@" '''(or)'...

2009-06-13T09:48:45Z

New page: '''Open DOS File''' '''Syntax:''' <br> DOSFC(AX-value, CX-value, file-name) EXCP=statement-label '''Entry:''' AX-value = "@3D00@" (read only) CX-value = "@0000@" '''(or)'...

New page

'''Open DOS File'''

'''Syntax:''' <br>
DOSFC(AX-value, CX-value, file-name) EXCP=statement-label
'''Entry:'''
AX-value = "@3D00@" (read only)
CX-value = "@0000@"

'''(or)'''

AX-value = "@3D42@" (read/write)
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:''' <br>
The DOSFC function call can be used to open a DOS file.
For read-only purposes, the function requires that the AX-value be set to "@3D00@" and the CX-value be set to null.

For read/write purposes, the function requires that the AX-value be set to "@3D42@" and the CX-value be set to null.

After the function is executed, the file will be open and the AX register will contain the file's handle. As noted earlier, it is the responsibility of the programmer to ensure that any file handles opened are closed upon completion of the desired function. Failure to comply will result in degradation of system performance and possible system hangs.

'''Example:'''<br>
! S SFOPEN,DSK
! O FOPEN,DSK
! L T00,E
! R QMONITOR
!
!========== OPEN DOS FILE HANDLE =============================
!
LENGTH 2 & LOCAL AX$,BX$,CX$,DX$ ! Define registers
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
!
100 FORMAT (ET) ! Screen format
!
1000 FORMAT DOSMESSAGE$ ! File input format
!
CLEAR ! Initialize variables
PRINT (0,100) ! Set typewriter mode
!
PRINT (0) "ENTER FILENAME TO OPEN:" ! 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$ = "@3D42@" ! Set AX to "OPEN FILE"
CX$ = "@0000@" ! Set CX to null
!
DOSFC(AX$,CX$,FILENAME$) EXCP=BRANCH1 ! Perform DOSFC call
!
FILEHANDLE$ = AX$ ! Save file handle
!
PRINT (0) FILENAME$;" OPENED SUCCESSFULLY."
PRINT (0) "PRESS ENTER TO CLOSE THE FILE."
INPUT (0) ""
!
AX$ = "@3E00@" ! Set AX to "CLOSE FILE"
BX$ = FILEHANDLE$ ! Set BX to file handle
CX$ = "@0000@" ! Set CX to null
DX$ = "@0000@" ! Set DX to null
!
DOSMS(AX$,BX$,CX$,DX$) EXCP=BRANCH2 ! Perform DOSMS call
!
PRINT (0) FILENAME$;" CLOSED SUCCESSFULLY."
PRINT (0) "PRESS ENTER TO STOP."
INPUT (0) ""
RUN "QMONITOR"
!
BRANCH1: ! Exception routine 1
PRINT (0) "FILE NOT OPENED." ! Display message
OPEN (1) "QERCOMET" ! Open error file
DOSCODE$ = "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
!
BRANCH2: ! Exception routine 2
PRINT (0) "FILE NOT CLOSED." ! 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) & RUN "QMONITOR" ! Close error file/exit
END

Open DOS File - Revision history

Badge at 09:51, 13 June 2009

Badge: New page: '''Open DOS File''' '''Syntax:''' DOSFC(AX-value, CX-value, file-name) EXCP=statement-label '''Entry:''' AX-value = "@3D00@" (read only) CX-value = "@0000@" '''(or)'...

Badge: New page: '''Open DOS File''' '''Syntax:'''
DOSFC(AX-value, CX-value, file-name) EXCP=statement-label '''Entry:''' AX-value = "@3D00@" (read only) CX-value = "@0000@" '''(or)'...