FDIM(3) BSD Programmer's Manual FDIM(3)
fdim, fdimf - positive difference functions
libm
#include <math.h> double fdim(double x, double y); float fdimf(float x, float y);
The fdim() and fdimf() functions return the positive difference between x and y. That is, if x-y is positive, then x-y is returned. If either x or y is an NaN, then an NaN is returned. Otherwise, the result is +0.0. Overflow or underflow may occur iff the exact result is not representable in the return type. No other exceptions are raised.
fabs(3), fmax(3), fmin(3), math(3)
The fdim() and fdimf() functions conform to ISO/IEC 9899:1999 ("ISO C99").
These routines first appeared in FreeBSD 5.3 and NetBSD 5.1. MirBSD #10-current February 9, 2014 1