SGI STL The STL portion of GNU libstdc++ that is used with gcc3 and gcc4 is licensed under the GPL, with the following exception: # As a special exception, you may use this file as part of a free software # library without restriction. Specifically, if other files instantiate # templates or use macros or inline functions from this file, or you compile # this file and link it with other files to produce an executable, this # file does not by itself cause the resulting executable to be covered by # the GNU General Public License. This exception does not however # invalidate any other reasons why the executable file might be covered by # the GNU General Public License.