Hi everybody. what happens if a "header include" is missing? because I unexpectedly notice that this code: main() {printf("hello");} works in linux(at least on my (mandriva spring 2007 )box) while it does not in windows(turbo C++). so finally, can I say : #include <stdio.h> is not always necessary! another question is : where does the compiler (or the linker) find the actual code of printf (whether or not one has written its prototype) -- View this message in context: http://old.nabble.com/about-including-header-files-tp26281601p26281601.html Sent from the gcc - Help mailing list archive at Nabble.com.