This is output from `defines' version 4.1.1, from your buddies at Newtware! Sun Apr 15 15:45:34 HKT 2012 BSD/OS bsd31.localdomain 3.1 BSDI BSD/OS 3.1 Kernel #4: Thu Oct 16 16:16:52 MDT 1997 polk@corp.BSDI.COM:/amd/demiurge/home/polk/sys-3.0patches/compile/GENERIC i386 cc = [cc] __BASE_FILE__ = "/tmp/def9398.c" __DATE__ = "Apr 15 2012" __FILE__ = "/tmp/def9398.c" __GNUC__ = 1 __INCLUDE_LEVEL__ = 0 __LINE__ = 4355 __STDC__ = 1 __TIME__ = "15:45:36" __VERSION__ = "1.42" __bsdi__ = 1 __i386__ = 1 bsdi = 1 i386 = 1 unix = 1 Checking other possibilities; should already be listed above: __DATE__ = "Apr 15 2012" __FILE__ = "/tmp/def9398.c" __GNUC__ = 1 __LINE__ = 25 __STDC__ = 1 __TIME__ = "15:45:36" Sizes of basic variable types: sizeof(char) = 8 bits sizeof(short) = 16 bits sizeof(int) = 32 bits sizeof(long) = 32 bits sizeof(float) = 32 bits sizeof(double) = 64 bits sizeof(long double) = 64 bits sizeof(char *) = 32 bits sizeof(char (*)(char)) = 32 bits