https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86125
Bug ID: 86125
Summary: missing -Wbuiltin-declaration-mismatch on a mismatched
return type
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: msebor at gcc dot gnu.org
Target Milestone: ---
GCC correctly diagnoses the strdup() declaration that differs from the
corresponding built-in in the type of its argument but fails to issue the same
warning for the declaration of strlen() that differs from the built-in in the
return type.
$ cat c.c && gcc -S -Wall c.c
char* strdup (int); // warning (good)
char* strlen (const char*); // missing warning
char* f (void)
{
return strlen ("123");
}
c.c:1:7: warning: conflicting types for built-in function ‘strdup’
[-Wbuiltin-declaration-mismatch]
char* strdup (int); // warning (good)
^~~~~~
