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Q40865: BC 6.00 Example to Manipulate File with OS/2 API Calls

Article: Q40865
Product(s): See article
Version(s): 6.00 6.00b 7.00
Operating System(s): OS/2
Keyword(s): ENDUSER | SR# S890125-57 | mspl13_basic
Last Modified: 1-FEB-1990

Below is a sample program that calls the following MS OS/2 API
functions:

   DosBufReset
   DosChgFilePtr
   DosClose
   DosOpen
   DosQFHandState
   DosQHandType
   DosRead
   DosSetFHandState
   DosWrite

This program can be compiled in Microsoft BASIC Compiler Version 6.00
or 6.00b for MS OS/2 and Microsoft BASIC Professional Development
System (PDS) Version 7.00 for MS OS/2.

The following is the sample program:

CONST TRUE=-1
CONST FALSE=0

REM $INCLUDE: 'BSEDOSFL.BI'
DEFINT A-Z
DIM sizel AS LONG
DIM reserved AS LONG
DIM buf AS STRING*512
DIM distance AS LONG
DIM NewPointer AS LONG

CLS
input "Enter the Filename : ";fl$
fl$=fl$+chr$(0)
openflag = 17
openmode = &h6092
PRINT
PRINT "Enter a Key to OPEN the file"
WHILE INKEY$="" : WEND
PRINT
x=DosOpen(varseg(fl$),sadd(fl$),handle,action,sizel,_
          filea,openflag,openmode,reserved)

IF (x) THEN
   print "An error occurred.  The number is : ";x
   end
ELSE
  print "The handle is : ";handle
  print "The action is : ";action
  print "The size is   : ";sizel
  print "The filea is  : ";filea
  print "The openflag  : ";openflag
  print "The openmode  : ";openmode
  size=512
  buffer$=string$(size/4,65)+string$(size/4,66)
  buffer$=buffer$+string$(size/4,67)+string$(size/4,68)+chr$(0)
  PRINT
  PRINT "Enter a Key to WRITE to the file"
  WHILE INKEY$="" : WEND
  PRINT
  x=DosWrite%(handle,varseg(buffer$),sadd(buffer$),size,nw)
  IF (x) THEN
    Print "An error occurred.  The number is : ";x
  ELSE
    print "The information was placed into the file."
    print "The number of bytes written was : ";nw
  END IF
END IF
PRINT
PRINT "Enter a Key to CLOSE the file"
WHILE INKEY$="" : WEND
PRINT

x=DosClose%(handle)
IF (x) THEN
   Print "An error occurred.  The number is : ";x
ELSE
   print "The file is closed." : print
END IF
PRINT
PRINT "Enter a Key to RE-OPEN the file"
WHILE INKEY$="" : WEND
PRINT
x=DosOpen(varseg(fl$),sadd(fl$),handle,action,sizel,_
          filea,openflag,openmode,reserved)

IF x THEN
   print "error: ";x
   stop
END IF
DONE=FALSE
WHILE NOT(done)
  size=256
  buf=string$(size,42)
  PRINT
  PRINT "Enter a Key to READ the file"
  WHILE INKEY$="" : WEND
  PRINT

  x=DosRead%(handle,varseg(buf),varptr(buf),size,nr)
  IF (x) THEN
    Print "An error occurred.  The number is : ";x
  ELSE
    IF nr=0 THEN
       PRINT "EOF Detected"
       DONE=TRUE
    ELSE
       PRINT "The number of bytes read is : ";nr
       PRINT "The bytes were : ";buf
    END IF
  END IF
WEND
  PRINT
  PRINT "Enter a Key to RESET the file BUFFER"
  WHILE INKEY$="" : WEND
  PRINT
  x=DosBufReset%(handle)
  IF (x) THEN
    Print "An error occurred.  The number is : ";x
  ELSE
    PRINT "The BUFFER was flushed"
  END IF
PRINT
PRINT "Enter a Key to CHANGE the file POINTER"
WHILE INKEY$="" : WEND
PRINT
distance=192
MoveType=0

x=DosChgFilePtr%(handle,distance,MoveType,NewPointer)
IF (x) THEN
  Print "An error occurred.  The number is : ";x
ELSE
  Print "The file pointer is moved.  The information will be read."
  size=256
  buf=string$(size,42)
  PRINT
  PRINT "Enter a Key to READ the file"
  WHILE INKEY$="" : WEND
  PRINT

  x=DosRead%(handle,varseg(buf),varptr(buf),size,nr)
  IF (x) THEN
    Print "An error occurred.  The number is : ";x
  ELSE
    IF nr=0 THEN
       PRINT "EOF Detected"
       DONE=TRUE
    ELSE
       PRINT "The number of bytes read is : ";nr
       PRINT "The bytes were : ";buf
    END IF
  END IF
END IF
PRINT
PRINT "Enter a Key to get the GET/Modify File Handle State"
WHILE INKEY$="" : WEND
PRINT

x=DosQFHandState%(handle,FileHandleState)
IF (x) THEN
   Print "An error occurred.  The number is : ";x
ELSE
   print "The filehandle state is : ";FileHandleState
END IF

NewHandState=&h0010
x=DosSetFHandState%(handle,NewHandleState)
IF (x) THEN
   Print "An error occurred.  The number is : ";x
ELSE
   print "The filehandle state was changed."
END IF

x=DosQFHandState%(handle,FileHandleState)
IF (x) THEN
   Print "An error occurred.  The number is : ";x
ELSE
   print "The filehandle state is : ";FileHandleState
END IF

x=DosQHandType%(handle,HandType,FlagWord)
IF (x) THEN
   Print "An error occurred.  The number is : ";x
ELSE
   IF (HandleType) THEN
       print "The handle type is a Device handle"
       print "The Flag Word is : ";Flag Word
   ELSE
       print "The handle type is a File-System handle"
   END IF
END IF
PRINT
PRINT "Enter a Key to CLOSE the file"
WHILE INKEY$="" : WEND
PRINT
x=DosClose%(handle)
IF (x) THEN
   Print "An error occurred.  The number is : ";x
ELSE
   print "The file is closed."
END IF
END

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