How can I find the header files of the C programming language in Linux?

Question

When I write C programs in Linux, and then compile them using gcc, I am always curious about where those header files are. For example, where stdio.h is. More g

Answer 1

If you use gcc, you can check a specific file with something like:

echo '#include ' | cpp -H -o /dev/null 2>&1 | head -n1

-H asks the preprocessor to print all included files recursively. head -n1 takes just the first line of output from that, to ignore any files included by the named header (though stdbool.h in particular probably doesn't).

On my computer, for example, the above outputs:

. /usr/lib/gcc/x86_64-linux-gnu/4.6/include/stdbool.h