Hi, I'm assuming -iprefix + -iwithprefix would locate DIR to same place as if specified by -idirafter, from below info gcc: `-iwithprefix DIR' `-iwithprefixbefore DIR' Append DIR to the prefix specified previously with `-iprefix', and add the resulting directory to the include search path. `-iwithprefixbefore' puts it in the same place `-I' would; `-iwithprefix' puts it where `-idirafter' would. However, it didn't with gcc-4.1.2 (FC7): (it was same with FC3, gcc-3.4.2) $ cat test.c /* this should be included by system directory's include/err.h */ #include <err.h> $ cat ./include/err.h #error "Choke me" $ gcc -iprefix ./ -iwithprefix include/ -c test.c In file included from test.c:2: ./include/err.h:1:2: error: #error "Choke me" $ gcc -idirafter ./include/ -c test.c $ With -idirafter -v, include search path was: #include "..." search starts here: #include <...> search starts here: /usr/local/include /usr/lib/gcc/i386-redhat-linux/4.1.2/include /usr/include ./include/ End of search list. Whereas -iwitprefix -v, include search path was: #include "..." search starts here: #include <...> search starts here: ./include/ /usr/local/include /usr/lib/gcc/i386-redhat-linux/4.1.2/include /usr/include So, as opposed to the gcc info, -iwithprefix does not seem to put DIR where -idirafter would. Thanks in advance. Best Regards, (Hiroki Kaminaga) t --