FDIM(3M) Mathematical Library Functions FDIM(3M)

fdim, fdimf, fdiml - compute positive difference between two floating-point numbers

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);

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

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

If xy 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.

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.

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.

See attributes(7) for descriptions of the following attributes:

Interface Stability Standard
MT-Level MT-Safe

math.h(3HEAD), feclearexcept(3M), fetestexcept(3M), fmax(3M), fmin(3M), attributes(7), standards(7)

July 12, 2006 SunOS 5.11