topic Re: LIB$SPAWN in Operating System - OpenVMS

LIB$SPAWN

Sk Noorul Hassan — Tue, 20 Dec 2005 06:13:47 GMT

Hi,
I am trying to execute one dcl script in a program using lib$spawn. It seems the program is not executing the script as I am not getting the required result. Is it possible to know, if the script has been successfully executed at DCL prompt or not ?

Re: LIB$SPAWN

Volker Halle — Tue, 20 Dec 2005 06:32:30 GMT

Hi,

do you check the system service status return value from the LIB$SPAWN call ?

Do you use the COMPLETION_STATUS parameter ? It will receive the exit status of the spawned subprocess.

You can also check with accounting, whether the subprocess has been created at all and what it's exit status is.

Volker.

Re: LIB$SPAWN

Wim Van den Wyngaert — Tue, 20 Dec 2005 06:44:16 GMT

And finally you can do @script/out=xxx
to capture the result, if any.

Wim

Re: LIB$SPAWN

Sk Noorul Hassan — Tue, 20 Dec 2005 06:51:38 GMT

Volker,
Can you write few lines how to get the completion status in a program, I am using the following line inside program

lib$spawn('@path:xx.com');

Re: LIB$SPAWN

Volker Halle — Tue, 20 Dec 2005 06:56:40 GMT

There should be a C example program in SYS$EXAMPLES, which includes a fully coded LIB$SPAWN invocation in C:

SYS$COMMON:[SYSHLP.EXAMPLES]ALPHA_LOGGER.C

status = LIB$SPAWN(0, &devnam, &devnam, &flags, 0, &pid, 0, 0,
subprocess_exit, 0);
if (status & SS$_NORMAL)

Volker.

Re: LIB$SPAWN

Sk Noorul Hassan — Tue, 20 Dec 2005 07:33:42 GMT

Volker,

Now after putting status check, I could found that lib$spawn is returning not sucess value i.e. DCL script is not executing. Can u guide me why this is not executing ??

Re: LIB$SPAWN

Volker Halle — Tue, 20 Dec 2005 07:44:13 GMT

You need to print both the STATUS value as returned from the LIB$SPAWN call (and the COMPLETION_STATUS, IF LIB$SPAWN returned with SS$_NORMAL).

Then use that value and translate it to the appropriate error message:

$ WRITE SYS$OUTPUT F$MESSAGE(value)
or
$ EXIT value

Make sure you use the correct radix (hex or decimal) depending on your printf format statement.

Volker.

Re: LIB$SPAWN

Sk Noorul Hassan — Tue, 20 Dec 2005 07:45:45 GMT

Hi, when I am trying to run this program

run/proc= program_name/output=err.txt program

I am getting 'no CLI present to perform function' error in the file err.txt

pls suggest

Re: LIB$SPAWN

Volker Halle — Tue, 20 Dec 2005 07:53:09 GMT

When you run your program in a SUB-process without DCL, there is no CLI to process a LIB$SPAWN...

It should work, if you run your program straight in your process with: $ RUN PROGRAM

Volker.

Re: LIB$SPAWN

Sk Noorul Hassan — Tue, 20 Dec 2005 10:59:05 GMT

Hi,

When I am running the program using "RUN prog_name", it is executing my DCL script and is not releasing the terminal. But when I am putting in detached mode, it is not executing my DCL script.

Pls suggest

Re: LIB$SPAWN

Jan van den Ende — Tue, 20 Dec 2005 11:05:59 GMT

Sk,

if you want to execute DCL in a dtetached process (or spawned from such, as you are trying), then use
$ RUN SYS$SYSTEM:LOGINOUT.EXE/INPUT=/OUTPUT=
This gives your process the CLI, which means, enables DCL.

HTH

Proost.

Have one on me.

jpe

Re: LIB$SPAWN

Robert_Boyd — Tue, 20 Dec 2005 11:08:22 GMT

Instead of

$ run/proc= program_name/output=err.txt program

Create a command procedure such as

run_program_name.com

Then you can use this command:

run/proc= program_name/output=err.txt /input=disk:[dir]run_program_name.com sys$system:loginout/authorize

This will create a complete DCL environment, including running the LOGIN.COM of the username the command is run under.

Robert

Re: LIB$SPAWN

Robert_Boyd — Tue, 20 Dec 2005 11:09:46 GMT

Ha! Jan, you and I must have been typing the same solution at the same time!

Proost!

Robert

Re: LIB$SPAWN

Sk Noorul Hassan — Tue, 20 Dec 2005 12:37:17 GMT

Hi,
I am trying to execute my DCL script using LIB$SPAWN inside a PASCAL program to create & enable a device on a terminal server port.

This script has to run along with the PASCAL code.

Re: LIB$SPAWN

John Gillings — Tue, 20 Dec 2005 15:35:13 GMT

>LIB$SPAWN inside a PASCAL program to
>create & enable a device on a terminal
>server port.

Why not create and enable the terminal server port directly from your program? See I/O Users Guide, Chapter Terminal Driver, in particular example 5-1 in Section 5.6.

http://h71000.www7.hp.com/doc/82FINAL/aa-pv6sg-tk/aa-pv6sg-tk.PDF

For further assistance, please log a case with your local customer support centre.

Re: LIB$SPAWN

Sk Noorul Hassan — Wed, 21 Dec 2005 08:00:17 GMT

Hi, Is it possible to use lib$do_command in this case, inside my pascal program.If yes, what environement definition is required for this.
Pls suggest

Re: LIB$SPAWN

Hein van den Heuvel — Wed, 21 Dec 2005 08:07:24 GMT

Yes, you can use LIB$DO_COMMAND, but that work a little like the Unix 'exec' and conflicts with your requirement "This script has to run along with the PASCAL code."

As per online doc:

LIB$DO_COMMAND
Execute Command
The Execute Command routine stops program execution and directs the command language interpreter (CLI) to execute a command that you supply as the argument. If successful, LIB$DO_COMMAND does not return control to the calling program. Instead, LIB$DO_COMMAND begins execution of the specified command.

If you want control to return to the caller, use LIB$SPAWN instead.

fwiw.
Hein.

Re: LIB$SPAWN

Jan van den Ende — Wed, 21 Dec 2005 08:07:48 GMT

Sk,

LIB$DO_COMMAND -- transfers -- control to the named procedure, and EXITs your image.
That means, it is THE LAST statement in your programm that gets executed.
As far as I understand you so far, that is NOT what you try to achieve!

hth,

Proost.

Have one on me.

jpe

Re: LIB$SPAWN

Sk Noorul Hassan — Wed, 21 Dec 2005 08:18:29 GMT

My final executable has to run in detached mode, so when I am trying to use LIB$SPAWN, it is not able to execute my dcl script inside. But if I am running 'RUN prog_name' it is executing the required dcl script.

Pls suggest

Re: LIB$SPAWN

Jan van den Ende — Wed, 21 Dec 2005 08:35:49 GMT

Sk,

re-read yesterdays answer by Robert Boyd and myself: RUNning SYS$SYSTEM:LOGINOUT with /INPUT= will execute in an environment that knows about DCL.

hth

Proost.

Have one on me.

jpe