Hallo Bruno, On 13 Oct 2010, at 02:48, Bruno Haible wrote: >> Then I believe the only viable option to provide stable support for >> multiple gnulib directories in a single tree is to add a switch to >> gnulib-tool to rewrite gnulib #include_next lines on import, so that >> both types of compilers include header files in the same order. > > Thanks for these thoughts, Gary and Eric. > > To sum up the discussion: > > - Double inclusion guards must depende on the macro_prefix.
I was wondering whether overloading macro_prefix like this is the best approach. It's certainly more flexible to have --macro-prefix to specify just the macro prefix, and a new --include-guard-prefix for include guard rewriting... but whether that flexibility will actually be useful I don't know. Certainly, even though we definitely need to rewrite the include guards for installed headers from libposix, I would have been perfectly happy to retain the default gl_INIT macro name for libposix's configure.ac. And, besides, LIBPOSIX_INIT seems like a misnomer to me. > - gnulib-tool needs an option --base-gnulib=.../gnulib-cache.m4 > that has two effects: > - It rewrites the include_next invocations for old compilers, > so that the program will always include > extra/gllib/stdlib.h -> main/gllib/stdlib.h -> /usr/include/stdlib.h > - It implies --avoid options for all the modules listed in the base > gnulib-cache.m4. (Otherwise modules get duplicated, causing malfunction > of modules that have global state, like sigaction, fchdir, and > similar.) > > - All typedefs that are defined in a .h file and are not triggered by a > module > for a function replacement must have a double definition guard, like we > did for > 'struct random_data'. This sounds like a robust and thorough approach to a tricky problem. Do you plan to work on this reasonably soon (within a couple of weeks)? If so, I'll wait until the patches arrive in master, and build from there for an improved topic/libposix that also addresses as many of your review comments as possible. Cheers, -- Gary V. Vaughan (g...@gnu.org)
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