https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97044
Bug ID: 97044 Summary: Undefined format macros because of include order on AIX Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: libstdc++ Assignee: unassigned at gcc dot gnu.org Reporter: clement.chigot at atos dot net Target Milestone: --- On AIX, C++ format macros like "PRIu32" might not be defined even if "cinttypes" is included. It happends when other headers which have a dependency on "inttypes.h" are included before. On AIX, __STDC_FORMAT_MACROS must be defined before "sys/inttypes.h" is included in order to have these macros defined. But with for example <cstring>, as "string.h" includes "sys/types" which included "sys/inttypes.h", __STDC_FORMAT_MACROS won't be defined when "sys/inttypes.h" is first included thus the format macros won't be defined. This program works on Linux but not on AIX. #include <cstring> #include <cinttypes> #include <iostream> int main(){ #ifdef PRIu32 std::cout << "PRIu32 defined" << std::endl; #else std::cout << "PRIu32 not defined" << std::endl; #endif } My question is what are the G++ standards saying on that ? Should <cinttypes> always defined "PRIu32"-like macros ? Or does the developers should be careful the order when are included the headers or always add -D__STDC_FORMAT_MACROS ? I would clearly go for one. Especially, because knowing that "#include <cstring>" must be after "#include <cinttypes>" if you want to use "PRIu32" is not obvious. Clément