https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122591
Bug ID: 122591
Summary: _Countof has wrong return type (not size_t)
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: sjames at gcc dot gnu.org
CC: [email protected]
Target Milestone: ---
See the thread starting at
https://lists.gnu.org/archive/html/bug-gnulib/2025-11/msg00048.html.
```
int global_array[12];
void test_return_type() {
static_assert(_Generic(typeof(_Countof global_array), typeof(sizeof(0)) : 1,
default : 0));
}
```
```
$ clang a.c -std=gnu2y -c # 21.1.5
$ gcc a.c -std=gnu2y -c # trunk from today
a.c: In function ‘test_return_type’:
a.c:6:3: error: static assertion failed
6 | static_assert(_Generic(typeof(_Countof global_array),
typeof(sizeof(0)) : 1, default : 0));
| ^~~~~~~~~~~~~
```
Clang has a test for exactly this functionality at clang/test/C/C2y/n3369.c
(added in
https://github.com/llvm/llvm-project/pull/133125/files#diff-5b20365a8a9f9b93411a2b5e156b5b74a6bad71a6cba0ae18dcb3a96defd7dde),
as does gnulib (which is how I spotted this).
Alex, you seem to have looked at the PR but also touched those gnulib tests
just last month -- did you test with trunk with your patches?
