http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60434
Bug ID: 60434
Summary: False -Wformat warnings about %lld and %Lf are given
on Windows
Product: gcc
Version: 4.8.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: egor_suvorov at mail dot ru
As you know, C++11 defines %Lf for writing and reading long double and %lf/%f
for double. I can successfully use them in printf in MinGW, but it gives me
false warnings when -Wformat enabled. However, it clearly knows something about
formatting, because if I disable C++11 standard, behavior is changed.
Consider the following example:
#include <cstdio>
int main() {
long double x = 123.45;
printf("%f\n", x); // Undefined
printf("%lf\n", x); // Undefined
printf("%Lf\n", x); // Expected '123.45' in C++11
double y = x;
printf("%f\n", y); // Expected '123.45' in C++11
printf("%lf\n", y); // Expected '123.45' in C++03/C++11
printf("%Lf\n", y); // Undefined
return 0;
}
It works when compiling with C++11 or C++03, but it works exactly is it should
to the corresponding standard. Looks like GCC's warnings system does not know
about 'L' modifier in C++11 and consider it spoiled.
I've already <a href="https://sourceforge.net/p/mingw/bugs/2190/";>reported</a>
this to MinGW team and they told me to redirect my report here.
