fdim, fdimf, fdiml

Parameters

Return value

If successful, returns the positive difference between x and y .

If a range error due to overflow occurs, +HUGE_VAL , +HUGE_VALF , or +HUGE_VALL is returned.

If a range error due to underflow occurs, the correct value (after rounding) is returned.

Error handling

Errors are reported as specified in Template:rllpt .

If the implementation supports IEEE floating-point arithmetic (IEC 60559),

• If either argument is NaN, NaN is returned.

Notes

Equivalent to fmax ( x - y, 0 ) except for the NaN handling requirements.

Example

#include <errno.h>
#include <fenv.h>
#include <math.h>
#include <stdio.h>
// #pragma STDC FENV_ACCESS ON
 
int main(void)
{
    printf("fdim(4, 1) = %f, fdim(1, 4)=%f\n", fdim(4,1), fdim(1,4));
    printf("fdim(4,-1) = %f, fdim(1,-4)=%f\n", fdim(4,-1), fdim(1,-4));
    //error handling
    errno = 0; feclearexcept(FE_ALL_EXCEPT);
    printf("fdim(1e308, -1e308) = %f\n", fdim(1e308, -1e308));
    if (errno == ERANGE)
        perror("    errno == ERANGE");
    if (fetestexcept(FE_OVERFLOW))
        puts("    FE_OVERFLOW raised");
}

fdim(4, 1) = 3.000000, fdim(1, 4)=0.000000
fdim(4,-1) = 5.000000, fdim(1,-4)=5.000000
fdim(1e308, -1e308) = inf
    errno == ERANGE: Numerical result out of range
    FE_OVERFLOW raised

References

See also