When I compile and run the example program shown below,
under RedHat Linux 5.2 (Kernel 2.0.36) with gcc
(v2.7.2.3), I get a segmentation error. The same code has
been run on many other Unix systems and even other versions
of Linux without failure. Granted fclose(NULL) is not a
useful thing to do, but nevertheless it should not cause a
segmentation error.

main()
{
     long *file_rep = 0x0;
     fclose(file_rep);
}