On 25/01/2017 06:40, Larry Evans wrote: > What if: > > ./lib1/foo.hpp: > #ifndef FOO_HPP > #define FOO_HPP > ... > #endif > > ./lib2/foo.hpp: > #ifndef FOO_HPP > #define FOO_HPP > ... > #endif > ,/main.cpp > #include "lib1/foo.hpp" > #include "lib2/foo.hpp" > > Is there any cpp option which can warn that > ./lib1/foo.hpp and ./lib2/foo.hpp have > the same include guards? > > Based on: > > https://gcc.gnu.org/onlinedocs/cppinternals/Guard-Macros.html#Guard-Macros > > > I would guess it would be simple to detect this since, according to > that cppinternals link: > > _cpp_pop_file_buffer remembers the controlling macro > associated with the file. Subsequent calls to > stack_include_file result in no buffer being pushed if the > controlling macro is defined, effecting the optimization. > > I recently had a need for this because boost/spirit has this > problem and correcting it has been tedious :( > > -regards, > Larry > Hello, I think that you may be misunderstand the paragraph. The name of the file is not remembered. It says just that the block "#ifndef FOO … #endif" is keeped and this is with this that gcc can take the "Multiple-Include Optimization". I think that what you want would be make a good new functionality, but it's not possible yet. If you find a error like this in a library, it's very nice to inform authors, or may be to propose a patch to them. Regards, Hogren
