https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79346
Bug ID: 79346
Summary: -Wundef should not warn for standard macros
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: preprocessor
Assignee: unassigned at gcc dot gnu.org
Reporter: mpeg.blue at free dot fr
CC: david at westcontrol dot com, jwakely.gcc at gmail dot com,
vincent-gcc at vinc17 dot net
Target Milestone: ---
ML discussion:
https://gcc.gnu.org/ml/gcc-help/2017-02/msg00000.html
According to Jonathan, -Wundef would warn for this legitimate use-case:
#if __STDC_VERSION__ < 199901L
#endif
Vincent suggested that there could be some kind of white-list for macros which
would not trigger the warning.
Macros suggested for the white-list:
https://gcc.gnu.org/ml/gcc-help/2017-02/msg00009.html
__STDC_VERSION__
__STDC_ISO_10646__
__STDC_MB_MIGHT_NEQ_WC__
__STDC_UTF_16__
__STDC_UTF_32__
Bug 49928 might be relevant.
