Adriaan van Os wrote:

Markus Gerwinski wrote:

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I attached some test code to this mail that reproduces a bug in GPC that just occurred in one of my projects. In short: When I link a Pascal unit to a C project, and a function in the Pascal unit calls RuntimeError, this results in a segfault when called from within the C code. (I'm using gpc-20050331 together with gcc-3.4.3.)

I think the problem is that the Pascal runtime is not initialized (see the thread "Default linker names").

Yes, seems so.

Please look at gpc-in-c.h, as there may be more things you'll have to do. (You can ignore the part about `--gpc-main' if you only have units on the Pascal side.)

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Pure Pascal projects are not affected, there the RuntimeError just works fine.

More precisely, if the main program is in Pascal, things are initialized/finalized automatically. So unless the C part insists on providing main(), you might consider this alternative. (You can then, of course, call a big C function which does most of the work from the Pascal main program, and the C functions can then call back to Pascal anytime.)

Frank

Markus Gerwinski wrote:

Frank Heckenbach wrote:

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Please look at gpc-in-c.h, as there may be more things you'll have to do. (You can ignore the part about `--gpc-main' if you only have units on the Pascal side.)

Okay, thanks. Calling _p_initialize solves the problem, of course. However, since it wasn't necessary in an earlier version, I wonder what has changed since?

When was it not necessary? gpc-in-c.h has existed for quite some time. If this particular case didn't crash before didn't mean that initialization wasn't necessary.

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Pure Pascal projects are not affected, there the RuntimeError just works fine.

More precisely, if the main program is in Pascal, things are initialized/finalized automatically. So unless the C part insists on providing main(), you might consider this alternative. (You can then, of course, call a big C function which does most of the work from the Pascal main program, and the C functions can then call back to Pascal anytime.)

Problem is, what I'm writing here is a library, so most probably there will be some users who insist on running it from a C main(). However, I could just provide all of my C demo programs with init()- and fini()-calls at the beginning and the end; that should be clear enough.

Yes, you might want to wrap them in library-init/fini routines, particularly if you need to do other initialization/finalization yourself.

If several such libraries are used together (or one such library with a Pascal main program), RTS initialization/finalization is done several times, but at a guick glance (you might want to check for yourself), I think they are idempotent, so no problem.

Frank