thanks for the prompt response.
I was just showing an example of the our source files. This whole software is composed on a couple hundred files (about 95% in Pascal, some C, and a couple in assembly). The whole thing is then linked. So there is only one file with the program header. All other source files just contain procedures in Pascal or C functions.
In this particular instance, I am trying to make a program where a C program calls the Pascal routine.
I don't know the influence of the ISO standard on this, but with Borland Pascal you can also just specify just "end. " as mainprogram to avoid unit initialisation (instead of begin end;)