https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109530
Bug ID: 109530
Summary: Warning "is used uninitialized" raised for an
initialized variable.
Product: gcc
Version: 12.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: patrick.pelissier at gmail dot com
Target Milestone: ---
For the following program:
#include <stdio.h>
#include <setjmp.h>
jmp_buf buf;
jmp_buf buf1;
typedef struct ry_s {
struct ry_s *next;
} ry_t[1];
struct ry_s *m_global;
static inline void
ry_init(ry_t state)
{
m_global = state;
}
static inline void
ry_clear(ry_t state)
{
m_global = state->next;
}
int func2(void)
{
for(_Bool b = 1 ; b ; b = 0)
for(ry_t test1 ; b ; ry_clear(test1), b = 0 )
if (ry_init(test1), setjmp (buf) == 0)
{
FILE *f = fopen("tmp","wt");
if ((setjmp (buf1) == 0) )
{
fprintf(f, "This is a text\n");
fclose(f);
}
}
return 0;
}
When running with "-O2 -Wall -Wextra", I get the following warning:
<source>: In function 'func2':
<source>:31:17: warning: 'f' is used uninitialized [-Wuninitialized]
31 | FILE *f = fopen("tmp","wt");
whereas f is obviously initialized in the statement.
I am confused by this warning.
