On Thu, 22 Nov 2018, Martin Liška wrote: > > (Multilib suffixes on include directories for C are more or less an > > implementation detail of how fixed headers are arranged in the case where > > sysroot headers suffixes are used; they aren't really expected to be a > > stable interface such that third-party software might install anything > > using them, but I'm not sure if this preinclude is meant to come from > > external software or be installed by GCC. > > It will come from glibc-devel package, and it's expected to be installed in: > usr/include/finclude/ for 64-bit header > and /usr/include/finclude/32/ for the 32-bit header.
So, to be clear, is that <sysroot><sysroot-headers-suffix><native-system-header-dir>/finclude/$($CC $CFLAGS $CPPFLAGS -print-multi-directory) ? (Where glibc would be what uses the $CC $CFLAGS $CPPFLAGS -print-multi-directory to determine where to install the file.) If so, you need to make sure that all of those pieces are properly used. * The sysroot and headers suffix in the case of a sysrooted toolchain. (Sysroot headers suffixes are for e.g. the case of a toolchain with both glibc and uClibc multilibs, so needing multiple sets of headers. Most toolchains with multiple sysroots using the same libc only need a single set of headers and don't use sysroot headers suffixes, only sysroot suffixes (non-headers), with appropriate arrangements being made for all the per-multilib headers, such as gnu/lib-names-*.h and gnu/stubs-*.h, to be copied into the common include directory.) * The native system header directory (which is /include not /usr/include for GNU Hurd, for example; see config.gcc). * Then finclude with the multilib (non-OS) suffix. And you need to consider what's right for non-sysrooted toolchains. If native, the above is right, but without the sysroot-related components. But what about a non-sysrooted cross toolchain? Certainly using the native directory would be wrong there. Also, what's right in the multiarch directory arrangements case - should it be <sysroot><sysroot-headers-suffix><native-system-header-dir>/<multiarch>/finclude instead? Would one of the Debian / Ubuntu GCC maintainers like to comment? Are there corresponding versions with /usr/local/include (LOCAL_INCLUDE_DIR, in general), before those with NATIVE_SYSTEM_HEADER_DIR? Even in the driver, the list of directories in cppdefault.c should at least serve as a guide to which directories you want to search and which get sysroots added (of course, the C++-specific ones are irrelevant here). -- Joseph S. Myers jos...@codesourcery.com
