https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71701
Bug ID: 71701
Summary: bogus token in -Wmaybe-uninitialized warning
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: palves at redhat dot com
Target Milestone: ---
This testcase makes gcc issue a confusing warning:
$ cat strtok.c
char *xstrdup (const char *) __attribute__ ((__returns_nonnull__));
#define PREFIX "some "
#include <string.h>
int
main ()
{
char *saveptr;
char *name = xstrdup (PREFIX "name");
char *tail = name + sizeof (PREFIX) - 1;
char *token = strtok_r (tail, " ", &saveptr);
return token [0];
}
$ /opt/gcc/bin/gcc -O2 strtok.c -c -Wall
strtok.c: In function ‘main’:
strtok.c:15:16: warning: ‘__s’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
return token [0];
~~~~~~^~~
$
It's confusing because nowhere in the sources there's "__s" variable.
"__s" here is actually the parameter of an inlined function,
in /usr/include/bits2.h:
__STRING_INLINE char *__strtok_r_1c (char *__s, char __sep, char **__nextp);
__STRING_INLINE char *
__strtok_r_1c (char *__s, char __sep, char **__nextp)
{
char *__result;
if (__s == NULL)
__s = *__nextp;
...
