fdim (3)

#include <math.h>

double fdim(double x, double y);

float fdimf(float x, float y);

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

Link with -lm.

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

fdimf(), fdiml():

_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;

or cc -std=c99

These functions return the positive difference, max(x-y,0), between their arguments.

On success, these functions return the positive difference.

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

If the result overflows, a range error occurs, and the functions return HUGE_VAL, HUGE_VALF, or HUGE_VALL, respectively.

See math_error(7) for information on how to determine whether an error has occurred when calling these functions.

The following errors can occur:

Range error: result overflow

An overflow floating-point exception (FE_OVERFLOW) is raised.

These functions do not set errno.

These functions first appeared in glibc in version 2.1.

Multithreading (see pthreads(7))

The fdim(), fdimf(), and fdiml() functions are thread-safe.

C99, POSIX.1-2001.

fmax(3)

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