Where are header files for GCC located?

Question

I want to manually add some header files like math.h and graphic.h for gcc but don't know where to put them.

Answer 1

First take a look in /usr/include or /usr/local/include.

If you find nothing there, try :

`gcc -print-prog-name=cc1plus` -v

This command asks gcc which C++ preprocessor it is using, and then asks that preprocessor where it looks for includes.

You will get a reliable answer for your specific setup.

Likewise, for the C preprocessor:

`gcc -print-prog-name=cc1` -v

Answer 2

To look for header locations just use the locate command:

locate -b '\math.h'
locate -b '\graphics.h'

or a simpler approach

locate \*/math.h
locate \*/graphics.h

If you are more familiar with regular expression use

locate -r \/math.h$

To make sure the database is up-to-date start:

sudo updatedb

That's the way I'm searching my headers location. It's much faster than using the find command.

Finding headers in not installed packages

For sake of completeness I post a one liner script which is in my mind very useful in finding apt packages involving a special header file.

#!/usr/bin/env bash
apt-file search $1 | cut -f 1 -d ":" | sort -u

Save this one liner for instance in your ~/.local/bin directory as e.g. aptfilesearch and make it executable with chmod +x aptfilesearch. Now you get a list of all packages including the header file you are searching for. Here a simple demonstration:

aptfilesarch math.h