On Tue, Sep 22, 2009 at 3:02 PM, Patrick Welche <prlw1@xxxxxxxxx> wrote: > On Tue, Sep 22, 2009 at 10:49:58AM +0200, Steffen Dettmer wrote: >> I've read here that someone could (should?) write >> #include <config.h> >> specifying a system header instead of the IMHO correct >> #include "config.h" > > I think this is the relevant part of the autoconf info file: > 4.9 Configuration Header Files > ============================== yeah, I knew this text (actually google did :)), but thought it would be some mistake? > ... > To provide for VPATH builds, remember to pass the C compiler a `-I.' > option (or `-I..'; whichever directory contains `config.h'). Even if > you use `#include "config.h"', the preprocessor searches only the > directory of the currently read file, i.e., the source directory, not > the build directory. > > With the appropriate `-I' option, you can use `#include <config.h>'. > Actually, it's a good habit to use it, because in the rare case when > the source directory contains another `config.h', the build directory > should be searched first. I though this was a kind of lazyness; just used "" and <> interchangingly without deeper meaning? I tought correct is: - with -I (and gcc), #include "config.h" is correct and works - with -I (and gcc), #include <config.h> is not correct but works anyway, because gcc searches system headers in user directories if it was not found in system directories - if #include <config.h> is really desired, I think for gcc it would be correct to use -isystem $(top_builddir) - for other compilers, -I often is -I but -isystem can be -j - other compilers may not distinguish that much or that flexible or not configurable where <file.h> is searched - on other compilers, #include <config.h> may not even work (when they use a fixed system directory and support no fallback search to user directories) Could * please correct my assumptions? oki, Steffen _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx http://lists.gnu.org/mailman/listinfo/autoconf
