What's the main difference between stdlib.h and cstdlib in C++?

Question

Hi,

I'm using EXIT_FAILURE macro, so I need to include stdlib.h or cstdlib. But I don't know what the difference is. Should I use cXXX style header file rather than XXX.h?

Thank you.

Answer 1

As EXIT_FAILURE is a macro, it makes no difference which you include. The cstdlib version will put the names of all the functions into the std namespace, so you can say things like:

std::exit(0);

but as macros don't respect namespaces, you can't say:

std::EXIT_FAILURE

Answer 2

<cstdlib> is just <stdlib.h> wrapped in the std namespace. You should use <cstdlib> in order to be keep your global namespace clean.