https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81609
Bug ID: 81609
Summary: incompatible extern C declarations of the same extern
function at local scope accepted
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: ---
Somewhat similar to bug 81608, G++ correctly rejects a function redeclaration
at local scope that's incompatible with a prior declaration of the same
function at namespace scope but only so long as the function has C++ language
linkage.
G++ fails to reject the same incompatible redeclaration of functions with C
language linkage.
Clang rejects both as expected.
$ cat t.C && gcc -S -Wall -Wextra -Wpedantic t.C
extern "C" {
int foo (void) { return 123; }
char* f (void)
{
extern char* foo (void);
return foo ();
}
}
int bar (void) { return 123; }
char* g (void)
{
extern char* bar (void);
return bar ();
}
t.C: In function ‘char* g()’:
t.C:18:16: error: local external declaration ‘char* bar()’ [-fpermissive]
extern char* bar (void);
^~~
t.C:14:5: note: does not match previous declaration ‘int bar()’
int bar (void) { return 123; }
^~~
