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

locate stdio.h

or

mlocate stdio.h

but locate relies on a database, if you have never updated it

sudo updatedb

you can also enquire gcc to know what are the default directories that are scanned by gcc itself:

gcc -print-search-dirs