Re: Passing a pointer between programs when using a dynamic call

Hi Stefan,

Is it possible to use a pointer as a parameter when calling another program?
The program call has to be made up dynamically and executed using qcmdexec
or system API…

You have two questions here, I think. Is it possible to pass a pointer as a parameter when calling a program? Yes! Provided that you are doing a direct program-to-program call.

Is it possible to pass a pointer via QCMDEXC or system()? No. Remember, QCMDEXC (and similar tools) receive one big character string from your program, and they interpret the contents of that character string, via scanning/parsing techniques. You can't pass any sort of variable (including a pointer, which is after all, a variable) when using those tools.

Program B gets invoked and need a mechanism to send back information to
program A.

Then you don't want to use QCMDEXC or it's friends.

Just to hide the complexity of the datastructure in program A my thought was to create a service program ( program C ) with procedures
that can be called by program B. It then seems reasonably that a
pointer must be used to “connect” the procedures in pgm C with the
datastructure in pgm A. Along the run it might be needed for program
C to change pointers in pgm A datastructure ( realloc of memory ).

I don't really understand this part of your message at all.

1) Why does PROGRAM A work this way? Why do you need so much flexibility in terms of the parameter list? Do you work for a software house where your software has to be able to call a customer's program with any arbitrary parameter list? I can't think of any other reason someone would do something like this.

2) I don't understand the "Program C" business at all. If you're passing the data via a parameter, how does a service program help? Why not pass the data via the service program instead of the parameter list?

3) Why does a pointer need to be used to "connect" your programs?

Am I out on very thin ice here? Better solutions?

Hard to say. I think we need more information to even begin to give you advice. Speaking for myself, at least, I really don't understand your scenario.