https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113886
Bug ID: 113886
Summary: new C23 length specifier with confusing diagnostic
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: jens.gustedt at inria dot fr
Target Milestone: ---
I am currently implementing the new %wN length specifiers for C23 in musl, and
the compiler support in gcc already works well for those N that actually exist,
it seems. Unfortunately the diagnostic for those where it doesn't are confusing
```
#include <stdio.h>
#include <stdint.h>
int main() {
uint32_t x = 2;
printf("%w31x\n", x); // works for 32 instead of 31
}
```
Here gcc (as of trunk on godbolt with '-std=c2x -Wall') tells me
<source>:6:14: warning: unknown conversion type character 'w' in format
[-Wformat=]
6 | printf("%w31x\n", x);
which is quite confusing because it is not the 'w' which wrong, but the number
following it.
