https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104693
Bug ID: 104693
Summary: Can't disable "comparison between pointer and integer"
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: charles.nicholson at gmail dot com
Target Milestone: ---
The following code causes gcc to emit a warning that does not seem to have a
diagnostic name, which makes it hard (impossible?) to disable:
=========================================
#include <stddef.h>
#include <stdbool.h>
bool foo(unsigned long not_a_pointer) {
return not_a_pointer == NULL;
}
=========================================
<source>: In function 'foo':
<source>:5:24: warning: comparison between pointer and integer
5 | return not_a_pointer == NULL;
| ^~
=========================================
Godbolt link: https://gcc.godbolt.org/z/chcxYevvf
I don't think anyone would argue that this is "good" (portable, defined, etc) C
code; it is vendor code that I'm stuck with. Additionally, on the architecture
I'm targeting, the implementation does the right thing: the unsigned long is
pointer-sized, and is compared against the NULL literal 0, which is used in
this context as a sentinel value. The code should use the literal 0 instead of
NULL, but it does not.
I have 3 suggestions, if they're helpful:
1. If this warning can be disabled, update the diagnostic message to include
the name as a hint on how to disable it.
2. If this warning can not be disabled, consider giving it a formal diagnostic
name and making it controllable via the standard methods (-Wno-, pragma, etc)
3. If this is truly heinous / unsafe enough, promote it to an error.
Thanks for all of your efforts on gcc!
Best,
Charles
