https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87775
Bug ID: 87775
Summary: error due __builtin_fprintf having the wrong type
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: msebor at gcc dot gnu.org
Target Milestone: ---
See also pr87774. GCC fails to compile the program below because it declares
__builtin_fprintf as taking void* rather than FILE* as the first argument (it's
a hack to get around FILE not necessarily being a known type when the built-in
is declared).
$ cat t.c && gcc -O2 -S -Wall -Wextra t.c
#include <stdio.h>
int f (const char*, ...);
int ff (FILE*, const char*, ...);
int sf (char*, const char*, ...);
void g (int i, FILE *fp, char *d)
{
(i ? printf : f)("abc");
(i ? fprintf : ff)(fp, "abc");
(i ? sprintf : sf)(d, "abc");
}
void h (int i, FILE *fp, char *d)
{
(i ? __builtin_printf : f)("abc");
(i ? __builtin_fprintf : ff)(fp, "abc");
(i ? __builtin_sprintf : sf)(d, "abc");
}
__typeof__ (fprintf) *pf = __builtin_fprintf;
t.c: In function ‘h’:
t.c:17:26: warning: pointer type mismatch in conditional expression
17 | (i ? __builtin_fprintf : ff)(fp, "abc");
| ^
t.c:17:26: error: called object is not a function or function pointer
17 | (i ? __builtin_fprintf : ff)(fp, "abc");
| ~~~~~~~~~~~~~~~~~~~~~~~^~~~~
t.c: At top level:
t.c:21:28: warning: initialization of ‘int (*)(FILE * restrict, const char *
restrict, ...)’ {aka ‘int (*)(struct _IO_FILE * restrict, const char *
restrict, ...)’} from incompatible pointer type ‘int (*)(void *, const char *,
...)’ [-Wincompatible-pointer-types]
21 | __typeof__ (fprintf) *pf = __builtin_fprintf;
| ^~~~~~~~~~~~~~~~~
