fdim

, fdimf

, fdiml

- compute positive difference between two floating-point numbers

Synopsis

c99 [ flag... ] file... -lm [ library... ]
#include <math.h>

double fdim(double x, double y);

float fdimf(float x, float y);

long double fdiml(long double x, long double y);

Description

These functions determine the positive difference between their arguments. If x is greater than y, x-y is returned. If x is less than or equal to y, +0 is returned.

Return Values

Upon successful completion, these functions return the positive difference value.

If x-y is positive and overflows, a range error occurs and fdim(), fdimf(), and fdiml() returns the value of the macro HUGE_VAL, HUGE_VALF, and HUGE_VALL, respectively.

If x or y is NaN, a NaN is returned.

Errors

These functions will fail if:

Range Error

The result overflows.

If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, the overflow floating-point exception will be raised.

Usage

An application wanting to check for exceptions should call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an exception has been raised. An application should either examine the return value or check the floating point exception flags to detect exceptions.

Attributes

See attributes(5) for descriptions of the following attributes:

See Also

feclearexcept(3M), fetestexcept(3M), fmax(3M), fmin(3M), math.h(3HEAD), attributes(5), standards(5)