This is output from `defines' version 4.1.1, from your buddies at Newtware! Wed Sep 29 13:54:47 EDT 1999 unix unix 3.2 2 i386 cc = [gcc] __BASE_FILE__ = "/tmp/def132.c" __DATE__ = "Sep 29 1999" __FILE__ = "/tmp/def132.c" __GNUC__ = 1 __INCLUDE_LEVEL__ = 0 __LINE__ = 9023 __STDC__ = 1 __TIME__ = "13:54:53" __VERSION__ = "1.42" i386 = 1 unix = 1 Checking other possibilities; should already be listed above: __DATE__ = "Sep 29 1999" __FILE__ = "/tmp/def132.c" __GNUC__ = 1 __LINE__ = 25 __STDC__ = 1 __TIME__ = "13:54:53" 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