1*8feb0f0bSmrg@c Copyright (C) 1988-2020 Free Software Foundation, Inc. 21debfc3dSmrg@c This is part of the GCC manual. 31debfc3dSmrg@c For copying conditions, see the file gcc.texi. 41debfc3dSmrg 51debfc3dSmrg@node Header Dirs 61debfc3dSmrg@chapter Standard Header File Directories 71debfc3dSmrg 81debfc3dSmrg@code{GCC_INCLUDE_DIR} means the same thing for native and cross. It is 91debfc3dSmrgwhere GCC stores its private include files, and also where GCC 101debfc3dSmrgstores the fixed include files. A cross compiled GCC runs 111debfc3dSmrg@code{fixincludes} on the header files in @file{$(tooldir)/include}. 121debfc3dSmrg(If the cross compilation header files need to be fixed, they must be 131debfc3dSmrginstalled before GCC is built. If the cross compilation header files 141debfc3dSmrgare already suitable for GCC, nothing special need be done). 151debfc3dSmrg 161debfc3dSmrg@code{GPLUSPLUS_INCLUDE_DIR} means the same thing for native and cross. It 171debfc3dSmrgis where @command{g++} looks first for header files. The C++ library 181debfc3dSmrginstalls only target independent header files in that directory. 191debfc3dSmrg 201debfc3dSmrg@code{LOCAL_INCLUDE_DIR} is used only by native compilers. GCC 211debfc3dSmrgdoesn't install anything there. It is normally 221debfc3dSmrg@file{/usr/local/include}. This is where local additions to a packaged 231debfc3dSmrgsystem should place header files. 241debfc3dSmrg 251debfc3dSmrg@code{CROSS_INCLUDE_DIR} is used only by cross compilers. GCC 261debfc3dSmrgdoesn't install anything there. 271debfc3dSmrg 281debfc3dSmrg@code{TOOL_INCLUDE_DIR} is used for both native and cross compilers. It 291debfc3dSmrgis the place for other packages to install header files that GCC will 301debfc3dSmrguse. For a cross-compiler, this is the equivalent of 311debfc3dSmrg@file{/usr/include}. When you build a cross-compiler, 321debfc3dSmrg@code{fixincludes} processes any header files in this directory. 33