```REMAINDER(3P)             POSIX Programmer's Manual            REMAINDER(3P)
```

## PROLOG         top

```       This manual page is part of the POSIX Programmer's Manual.  The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
```

## NAME         top

```       remainder, remainderf, remainderl — remainder function
```

## SYNOPSIS         top

```       #include <math.h>

double remainder(double x, double y);
float remainderf(float x, float y);
long double remainderl(long double x, long double y);
```

## DESCRIPTION         top

```       The functionality described on this reference page is aligned with
the ISO C standard. Any conflict between the requirements described
here and the ISO C standard is unintentional. This volume of
POSIX.1‐2008 defers to the ISO C standard.

These functions shall return the floating-point remainder r=x−ny when
y is non-zero. The value n is the integral value nearest the exact
value x/y.  When |n−x/y|=½, the value n is chosen to be even.

The behavior of remainder() shall be independent of the rounding
mode.
```

## RETURN VALUE         top

```       Upon successful completion, these functions shall return the
floating-point remainder r=x−ny when y is non-zero.

On systems that do not support the IEC 60559 Floating-Point option,
if y is zero, it is implementation-defined whether a domain error
occurs or zero is returned.

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

If x is infinite or y is 0 and the other is non-NaN, a domain error
shall occur, and a NaN shall be returned.
```

## ERRORS         top

```       These functions shall fail if:

Domain Error
The x argument is ±Inf, or the y argument is ±0 and the
other argument is non-NaN.

If the integer expression (math_errhandling & MATH_ERRNO)
is non-zero, then errno shall be set to [EDOM].  If the
integer expression (math_errhandling & MATH_ERREXCEPT) is
non-zero, then the invalid floating-point exception shall
be raised.

These functions may fail if:

Domain Error
The y argument is zero.

If the integer expression (math_errhandling & MATH_ERRNO)
is non-zero, then errno shall be set to [EDOM].  If the
integer expression (math_errhandling & MATH_ERREXCEPT) is
non-zero, then the invalid floating-point exception shall
be raised.

The following sections are informative.
```

## EXAMPLES         top

```       None.
```

## APPLICATION USAGE         top

```       On error, the expressions (math_errhandling & MATH_ERRNO) and
(math_errhandling & MATH_ERREXCEPT) are independent of each other,
but at least one of them must be non-zero.
```

## RATIONALE         top

```       None.
```

## FUTURE DIRECTIONS         top

```       None.
```

## SEE ALSO         top

```       abs(3p), div(3p), feclearexcept(3p), fetestexcept(3p), ldiv(3p)

The Base Definitions volume of POSIX.1‐2008, Section 4.19, Treatment
of Error Conditions for Mathematical Functions, math.h(0p)
```

## COPYRIGHT         top

```       Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) In the event of any discrepancy between this version and
the original IEEE and The Open Group Standard, the original IEEE and
The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.unix.org/online.html .

Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                 2013                       REMAINDER(3P)
```

Pages that refer to this page: math.h(0p)remquo(3p)