$ gcc -Wall vatest.c -o vatest
vatest.c: In function `vatest_':
vatest.c:17: warning: passing arg 2 of `vatest__' from incompatible pointer type
$ ./vatest
Segmentation fault
$ file vatest
vatest: ELF 64-bit LSB executable, AMD x86-64, version 1 (SYSV), for GNU/Linux 2.6.4, dynamically linked (uses shared libs), for GNU/Linux 2.6.4, not stripped