C program compiled with cygwin in Windows works, segmentation fault under Linux. Is cygwin GCC 'bad'?

Question

For my Programming 102 class we are asked to deliver C code that compiles and runs under Linux. I don\'t have enough spare space on my hard drive to install Linux alongside Wind

Answer 1

Like others have said, you might want to post some of your code here, even if that's not the real point of your question. It might still be a good learning experience to have everyone here poke through your code and see if they can find what caused the segfault.

But yeah, the problem is that there are so many platform-dependent, as well as basically random, factors influencing a C program. Virtual memory means that sometimes, accessing unallocated memory will seem to work, because you hit an unused part of a page that's been allocated at some earlier point. Other times, it'll segfault because you hit a page that hasn't been allocated to your process at all. And that is really impossible to predict. It depends on where your memory was allocated, was it at the edge of a page, or in the middle? That's up to the OS and the memory manager, and which pages have been allocated so far, and...... You get the idea. Different compilers, different versions of the same compilers, different OS'es, different software, drivers or hardware installed on the system, anything can change whether or not you get a segfault when you access unallocated memory.

As for the TA's claim that cygwin is more "lax", that's rubbish, for one simple reason. Neither compiler caught the bug! If the "native" GCC compiler had truly been less lax, it would have given you an error at compile-time. Segfaults are not generated by the compiler. There's not much the compiler can do to ensure you get a segfault instead of a program that seemingly works.