https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93406
Bug ID: 93406
Summary: No argument checking for wchar_t variants of
print-like functions
Product: gcc
Version: 7.4.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: jerome.h...@planete-sciences.org
Target Milestone: ---
Hi,
There is no output of -Wformat for functions using wchar_t format specifiers.
Let the following program:
/////////////////////////////////////////////////////
#include <time.h>
#include <stdio.h>
#include <wchar.h>
int main(void)
{
wchar_t wbuf[128];
char cbuf[128];
time_t now = time(NULL);
swprintf(wbuf, sizeof(wbuf)/sizeof(*wbuf), L"%d", now);
snprintf(cbuf, sizeof(cbuf)/sizeof(*cbuf), "%d", now);
printf("wbuf:%S\n", wbuf);
printf("cbuf:%s\n", cbuf);
return 0;
}
/////////////////////////////////////////////////////
#####################################################
c++ -Wall -o rapport.elf rapport.cpp
rapport.cpp: In function ‘int main()’:
rapport.cpp:11:55: warning: format ‘%d’ expects argument of type ‘int’, but
argument 4 has type ‘time_t {aka long int}’ [-Wformat=]
snprintf(cbuf, sizeof(cbuf)/sizeof(*cbuf), "%d", now);
^
#####################################################
The mismatch between format specifier and argument is only reported for char
functions, not for wchar_t functions.
I have seen this problem on:
c++ (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0
C++ (GCC) 8.2.0
