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From: "guojiufu at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/55602] New: Does not generate Error message for redefined macros Date: Wed, 05 Dec 2012 03:44:00 -0000 [thread overview] Message-ID: <bug-55602-4@http.gcc.gnu.org/bugzilla/> (raw) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55602 Bug #: 55602 Summary: Does not generate Error message for redefined macros Classification: Unclassified Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassigned@gcc.gnu.org ReportedBy: guojiufu@gmail.com gcc and g++ generate warning message(do not generate any information if there is '#pragma GCC system_header' is the header) instead an error message for redefined macros. While in standard it seems require an error. Second paragraph of section "Macro replacement" in C standard: -------- An identifier currently defined as an object-like macro shall not be redefined by another #define preprocessing directive unless the second definition is an object-like macro definition and the two replacement lists are identical. Likewise, an identifier currently defined as a function-like macro shall not be redefined by another #define preprocessing directive unless the second definition is a function-like macro definition that has the same number and spelling of parameters, and the two replacement lists are identical. ---------- C++ standard: Second paragraph of section "Macro replacement" --------- An identifier currently defined as an object-like macro may be redefined by another #define preprocessing directive provided that the second definition is an object-like macro definition and the two replacement lists are identical, otherwise the program is ill-formed. Likewise, an identifier currently defined as a function-like macro may be redefined by another #define preprocessing directive provided that the second definition is a function-like macro definition that has the same number and spelling of parameters, and the two replacement lists are identical, otherwise the program is ill-formed. ------------------ case: a.h ---------------- #define A 1 #define A 2 --------------- a.c --------------- #include "a.h" int main(){ return A; } --------------
next reply other threads:[~2012-12-05 3:44 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-12-05 3:44 guojiufu at gmail dot com [this message] 2012-12-05 5:00 ` [Bug preprocessor/55602] " pinskia at gcc dot gnu.org 2012-12-10 11:58 ` guojiufu at gmail dot com 2012-12-10 11:59 ` guojiufu at gmail dot com 2012-12-10 12:02 ` guojiufu at gmail dot com 2012-12-26 2:26 ` guojiufu at gmail dot com
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