COBOL 3.0 Example Calling DosStartSession API in MS OS/2
PSS ID Number: Q37479 Article last modified on 04-20-1993
3.00 OS/2
| The information in this article applies to: |
| - Microsoft COBOL for OS/2, version 3.0 |
Summary: The example below demonstrates how to make the DosStartSession API call from a COBOL program running in MS OS/2 protected mode. Some of the requirements are that you compile with the PCOBOL compiler and LINK with the /NOP option as illustrated below. The COBOL.DIR file should contain the LITLINK directive so the compiler can generate a machine-code call to the DOSCALLS.LIB module. The COBOL.DIR file should contain only the LITLINK directive.
More Information: In the example below, the program BEEPC.EXE is started as a new screen group. BEEPC.EXE is located in the directory C:. The entire path and program name must be specified in the program name parameter of the DosStartSession API call. The compile line is as follows: PCOBOL DOSSTART.COB; The link line is as follows: LINK DOSSTART/NOP/NOD,,,PCOBOL+DOSCALLS; Note: the DOSCALLS.LIB should be in a directory pointed to by the LibPath environment variable in CONFIG.SYS or CONFIG.OS2. For more information on this subject, please see the “Microsoft Operating System/2 Programmer’s Toolkit Programmer’s Reference” manual. The following is a code example:
$SET ANS85 OSVS
* ANS85 is needed to enable the 'end-if' (scope delimiter)
* syntax and OSVS is needed for 'return-code'
Identification division.
Program-Id. DOSSTART.
Data division.
Working-storage section.
01 dos-start-params.
* Use COMP-5 to ensure suitable byte order for i86 CPU
* Start-data is passed to the API call
03 start-data.
05 start-data-Length pic x(2) comp-5 value 24.
05 start-data-Related pic x(2) comp-5.
05 start-data-FgBg pic x(2) comp-5.
05 start-data-TraceOpt pic x(2) comp-5.
05 start-data-PgmTitle pic x(4) comp-5.
05 start-data-PgmName pointer.
05 start-data-PgmInputs pointer.
05 start-data-TermQ pic x(4) comp-5 value 0.
* SessID and PID may be returned by the API call, but are
* not used in this example.
03 sessID pic x(4) comp-5.
03 PID pic x(4) comp-5.
* The program name must be in ASCIIZ format, and *MUST* be
* fully qualified - that is, it must include the drive & path
01 program-name.
03 filler pic x(16) value "C:\OS2\BEEPC.EXE".
03 filler pic x value x"00".
* A command-line could be passed to the session here
01 argument pic x(64) value spaces.
01 temp pic x.
procedure division.
initialization-para.
* Start process as a child (could be independent)
move 1 to start-data-related
* Run in foreground (not background)
move 0 to start-data-FgBg
* No need for tracing
move 0 to start-data-TraceOpt
* Title can be null, to use name as title
move 0 to start-data-PgmTitle
* Point to the pgm name from start-data
set start-data-PgmName to address of program-name
* Point to the arguments, blank in this example
set start-data-PgmInputs to address of argument
* No queues are used in this example
move 0 to start-data-TermQ.
start-the-session.
display "calling DosStartSession now"
* The OS/2 API parameters are in Pascal order
* (reverse COBOL order):
call "DosStartSession"
using by reference PID
by reference SessID
by reference start-data
if return-code = 0
display "session executed ok"
else
display
"startsession failed : return code = " return-code
end-if.
wait-here.
display "press enter to return to OS/2" with no advancing
accept temp
stop run.
Additional reference words: 3.00 Copyright Microsoft Corporation 1993.
