### Table of Contents

# fmod

## NAME

fmod, fmodf, fmodl - floating-point remainder value function

## SYNOPSIS

c99 [ *flag*… ] *file*… **-lm** [ *library*… ]

#include <math.h>

**double fmod**(**double** *x*, **double** *y*);

**float fmodf**(**float** *x*, **float** *y*);

**long double fmodl**(**long double** *x*, **long double** *y*);

## DESCRIPTION

These functions return the floating-point remainder of the division of *x* by *y*.

## RETURN VALUES

These functions return the value *x* − *i* * *y*, for some integer *i* such that, if *y* is non-zero, the result has the same sign as *x* and magnitude less than the magnitude of *y*.

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

If *y* is 0, a domain error occurs and a NaN is returned.

If *x* is infinite, a domain error occurs and a NaN is returned.

If *x* is ±0 and *y* is not 0, ±0 is returned.

If *x* is not infinite and *y* is ±Inf, *x* is returned.

## ERRORS

These functions will fail if:

**Domain Error**

The *x* argument is infinite or *y* is 0.

If the integer expression (**math_errhandling** & **MATH_ERREXCEPT**) is non-zero, the invalid floating-point exception is 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(7) for descriptions of the following attributes:

## SEE ALSO

**math.h**(3HEAD), **feclearexcept**(3M), **fetestexcept**(3M), **isnan**(3M), attributes(7), standards(7)