What is time_t ultimately a typedef to?

Question

I searched my Linux box and saw this typedef:

typedef __time_t time_t;

But I could not find the __time_t definition.

Answer 1

Typically you will find these underlying implementation-specific typedefs for gcc in the bits or asm header directory. For me, it's /usr/include/x86_64-linux-gnu/bits/types.h.

You can just grep, or use a preprocessor invocation like that suggested by Quassnoi to see which specific header.