float_t, double_t

typedef /*implementation defined*/ float_t

typedef /*implementation defined*/ double_t

The types float_t and double_t are floating types at least as wide as float and double, respectively, and such that double_t is at least as wide as float_t. The value of FLT_EVAL_METHOD determines the types of float_t and double_t.

Example

#include <float.h>
#include <math.h>
#include <stdio.h>
 
int main(void)
{
    printf("%d\n", FLT_EVAL_METHOD);
    printf("%zu  %zu\n", sizeof(float),sizeof(float_t));
    printf("%zu  %zu\n", sizeof(double),sizeof(double_t));
    return 0;
}

0
4  4
8  8

References

• C11 standard (ISO/IEC 9899:2011):
• 7.12 Mathematics <math.h> (p: 231)
• C99 standard (ISO/IEC 9899:1999):
• 7.12 Mathematics <math.h> (p: 212)