# nextupl (3)

# NAME

nextup, nextupf, nextupl, nextdown, nextdownf, nextdownl - return next floating-point number toward positive/negative infinity# SYNOPSIS

#define _GNU_SOURCE/* See feature_test_macros(7) */#include <math.h>

double nextup(doublex);float nextupf(floatx);long double nextupl(long doublex);

Link withdouble nextdown(doublex);float nextdownf(floatx);long double nextdownl(long doublex);

*-lm*.

# DESCRIPTION

The**nextup**(),

**nextupf**(), and

**nextupl**() functions return the next representable floating-point number greater than

*x*. If

*x*is the smallest representable negative number in the corresponding type, these functions return -0. If

*x*is 0, the returned value is the smallest representable positive number of the corresponding type. If

*x*is positive infinity, the returned value is positive infinity. If

*x*is negative infinity, the returned value is the largest representable finite negative number of the corresponding type. If

*x*is Nan, the returned value is NaN. The value returned by

*nextdown(x)*is

*-nextup(-x)*, and similarly for the other types.

# RETURN VALUE

See DESCRIPTION.# VERSIONS

These functions first appeared in glibc in version 2.24.# ATTRIBUTES

For an explanation of the terms used in this section, see**attributes**(7).

Interface | Attribute | Value |

nextup (), nextupf (), nextupl (), nextdown (), nextdownf (), nextdownl () | Thread safety | MT-Safe |

# CONFORMING TO

These functions are described in*IEEE Std 754-2008 - Standard for Floating-Point Arithmetic*and

*ISO/IEC TS 18661*.

# SEE ALSO

**nearbyint**(3),

**nextafter**(3)