On 2017-05-30 17:10 +0200, Vincent Lefevre wrote: > Is it normal that -std=c90 -pedantic-errors allows to use > > #include <stdint.h> > > ? > > This is annoying when one wants to check for code portability > (and bugs). Let's ask libc developers and get their opinion about using stdint.h in C90... Hi all, There has been an argue in gcc-help about using stdint.h (or other C99 headers) in C90. Some people think that's not portable. They expect an error or a warning when they include stdint.h in C90. There are some options: 0) Do nothing, if we have a good reason. 1) Let GCC complains the header with name "stdint.h" in C90 mode, maybe with a flag. (Maybe -Wnew-std-headers?) I think it's stupid to make the decision according to the filename. 2) Disable stdint.h in C90, using something like #if defined(__STRICT_ANSI__) && __STDC_VERSION__ < 199901L #error "This is a C99 header. Please use -std=c99." #endif Maybe we need to check feature test macros (_POSIX_C_SOURCE etc) as well. 3) Warn about using stdint.h in C90. #if defined(__STRICT_ANSI__) && __STDC_VERSION__ < 199901L #warning "This is a C99 header. Recommend to use -std=c99." #endif 4) Let GCC define something like "__PEDANTIC__" with "-Wpedantic" and write... #if defined(__STRICT_ANSI__) && __STDC_VERSION__ < 199901L #if __PEDANTIC__ > 1 /* with -Werror=pedantic. */ #error "This is a C99 header. Please use -std=c99." #elif __PEDANTIC__ > 0 /* with -Wpedantic. */ #warning "This is a C99 header. Recommend to use -std=c99." #endif in stdint.h. 5) Let GCC accept a strange pragma to check C Standard version: #pragma GCC require(stdc, 199901L) And GCC would produce pedantic warning/error according to the flag while it see this pragma. Which option should we take? -- Xi Ruoyao <ryxi@xxxxxxxxxxxxxxxxx> School of Aerospace Science and Technology, Xidian University
