Question

I am currently working on a C project that needs to be fairly portable among different building environments. The project targets POSIX-compliant systems on a hosted C environment.

One way to achieve a good degree of portability is to code under conformance to a chosen standard, but it is difficult to determine whether a given translation unit is strict-conformant to ISO C. For example, it might violate some translation limits, or it might be relying on an undefined behavior, without any diagnostic message from the compilation environment. I am not even sure whether it is possible to check for strict conformance of large projects.

With that in mind, is there any compiler, tool or method to test for strict ISO C conformance under a given standard (for example, C89 or C99) of a translation unit?

Any help is appreciated.

Answer 1

It is not possible in general to find undefined run-time behavior. For example, consider

void foo(int *p, int *q)
{
    *p = (*q)++;
    ...

which is undefined if p == q. Whether that can happen can’t be determined ahead of time without solving the halting problem.

(Edited to fix mistake caf pointed out. Thanks, caf.)