Compute the positive difference between two floating-point numbers
#include <math.h> double fdim( double x, double y ); float fdimf( float x, float y ); long double fdiml( long double x, long double y );
The fdim(), fdimf(), and fdiml() functions compute the positive difference between two floating-point numbers. If x is greater than y, then these function return x - y. If x is less than or equal to y, these functions return +0.
To check for error situations, use feclearexcept() and fetestexcept(). For example:
The positive difference.
If: | These functions return: | Errors: |
---|---|---|
x - y is positive and overflows | Inf | FE_OVERFLOW |
The correct value would cause underflow | The correct value, after rounding | — |
x or y is NaN | NaN | — |
These functions raise FE_INEXACT if the FPU reports that the result can't be exactly represented as a floating-point number.
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | No |
Thread | Yes |