How to add a default include path for GCC in Linux?

313
votes

I'd like gcc to include files from $HOME/include in addition to the usual include directories, but there doesn't seem to be an analogue to $LD_LIBRARY_PATH.

I know I can just add the include directory at command line when compiling (or in the makefile), but I'd really like a universal approach here, as in the library case.

4
linuxgccincludeenvironment-variables
Here is link to GCC 4.8.1 manual where C_INCLUDE_PATH and CPLUS_INCLUDE_PATH environment variables are documented. - mloskot

4 Answers

428
votes

Try setting C_INCLUDE_PATH (for C header files) or CPLUS_INCLUDE_PATH (for C++ header files).

As Ciro mentioned, CPATH will set the path for both C and C++ (and any other language).

More details in GCC's documentation.

52
votes

Create an alias for gcc with your favorite includes.

alias mygcc='gcc -I /whatever/'
10
votes

just a note: CPLUS_INCLUDE_PATH and C_INCLUDE_PATH are not the equivalent of LD_LIBRARY_PATH. LD_LIBRARY_PATH serves the ld (the dynamic linker at runtime) whereas the equivalent of the former two that serves your C/C++ compiler with the location of libraries is LIBRARY_PATH.

9
votes

A gcc spec file can do the job, however all users on the machine will be affected.

See HOWTO Use the GCC specs file