https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94654
Bug ID: 94654
Summary: printf calls with floats
Product: gcc
Version: 9.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: tydeman at tybor dot com
Target Milestone: ---
/*
* These should all print the same thing: 2e+35
*/
#include <stdio.h>
#define FMT "%.14g"
#define FMTL "%.14Lg"
int main(void){
const long double ld = 2e+35L;
const double d = 2e+35;
const float f = 2e+35F;
(void)printf("1:" FMT "\n", f );
(void)printf("2:" FMT "\n", (double)f );
(void)printf("3:" FMT "\n", 2e+35F );
(void)printf("4:" FMT "\n", (double)2e+35F );
(void)printf("5:" FMT "\n", (float)d );
(void)printf("6:" FMT "\n", (float)ld );
(void)printf("a:" FMT "\n", d );
(void)printf("b:" FMT "\n", 2e+35 );
(void)printf("c:" FMTL "\n", ld );
(void)printf("d:" FMTL "\n", 2e+35L );
return 0;
}
The first 6 print as if %f (which is wrong).
The last 4 print as if %e
varargs are supposed to promote float to double.
