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From: "sebor at roguewave dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/37064] New: missing warning on pure function with side-effects Date: Fri, 08 Aug 2008 19:45:00 -0000 [thread overview] Message-ID: <bug-37064-1186@http.gcc.gnu.org/bugzilla/> (raw) [-- Warning: decoded text below may be mangled, UTF-8 assumed --] [-- Attachment #1: Type: text/plain, Size: 1227 bytes --] gcc assumes that functions defined with the pure attribute have no side effects and do not modify program state, including through pointers passed to such functions as arguments. The function below does modify the object pointed to by its argument. It would be useful if gcc issued a diagnostic for this and other similar violations of the "pure" assumption, analogously to how it diagnoses noreturn functions that do return. $ cat -n t.C && g++ -c -O2 -Wall -W t.C 1 int f0 () __attribute ((noreturn)); 2 int f0 () { return 0; } 3 4 int f1 (int*) __attribute ((pure)); 5 int f1 (int *i) 6 { 7 *i = 0; 8 return 0; 9 } 10 t.C: In function int f0(): t.C:2: warning: function declared noreturn has a return statement t.C:2: warning: noreturn function does return -- Summary: missing warning on pure function with side-effects Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: sebor at roguewave dot com http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37064
next reply other threads:[~2008-08-08 19:45 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2008-08-08 19:45 sebor at roguewave dot com [this message] 2008-08-08 19:49 ` [Bug c/37064] " sebor at roguewave dot com 2008-08-08 20:55 ` rguenth at gcc dot gnu dot org 2008-08-08 21:02 ` pinskia at gcc dot gnu dot org
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