Q40873: BC 6.00 Example of OS/2 API Function Call DosDupHandle

Article: Q40873
Product(s): See article
Version(s): 6.00 6.00b 7.00
Operating System(s): OS/2
Keyword(s): ENDUSER | SR# S890125-58 | mspl13_basic
Last Modified: 1-FEB-1990

Below is a sample program that makes a call to the MS OS/2 API
function DosDupHandle. It also uses the following MS OS/2 API
functions:

   DosOpen
   DosRead
   DosWrite
   DosClose

This program can be compiled in Microsoft BASIC Compiler Versions 6.00
and 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

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$(size/4,66)+string$(size/4,67)
  buffer$=buffer$+string$(size/4,68)+chr$(0)

  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

x=DosClose%(handle)
IF (x) THEN
   Print "An error occurred.  The number is : ";x
ELSE
   print "The file is closed." : print
END IF
print "Enter Any Key OPEN file and DUPLICATE Handle..."
while inkey$="" :wend

x=DosOpen(varseg(fl$),sadd(fl$),handle,action,sizel,_
          filea,openflag,openmode,reserved)
x=DosDupHandle%(handle,newhandle)
  IF (x) THEN
    Print "An error occurred.  The number is : ";x
  ELSE
    Print "Handle was Duplicated."
  END IF
PRINT
PRINT "Enter any Key to READ with Both handles"
PRINT
WHILE INKEY$="" : WEND
size=256
buf=string$(size,42)
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"
    ELSE
       PRINT "ORIGINAL HANDLE"
       PRINT "The number of bytes read is : ";nr
       PRINT "The bytes were : ";buf
    END IF
  END IF
size=256
buf=string$(size,42)
x=DosRead%(newhandle,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"
    ELSE
       PRINT "NEW HANDLE"
       PRINT "The number of bytes read is : ";nr
       PRINT "The bytes were : ";buf
    END IF
  END IF

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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