Considering '#defines' are done in a textual pre-precessing by the C pre-processor, they don't know much at all about the C language. You can define out int, lo

Considering '#defines' are done in a textual pre-precessing by the C pre-processor, they don't know much at all about the C language. You can define out int, long, struct or anything. I have seen many people redefine 'for' and 'while'. These people often argue that it is an improvement. cpp #define sizeof(x) (size)sizeof(x) sizeof(UU) ^D # 1 "<stdin>" # 1 "<built-in>" # 1 "<command-line>" # 31 "<command-line>" # 1 "/usr/include/stdc-predef.h" 1 3 4 # 32 "<command-line>" 2 # 1 "<stdin>" (size)sizeof(UU)