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nextup(3) — Linux manual page

nextup(3)                Library Functions Manualnextup(3)

NAME        top

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

LIBRARY        top

       Math library (libm,-lm)

SYNOPSIS        top

#define _GNU_SOURCE/* See feature_test_macros(7) */#include <math.h>double nextup(doublex);float nextupf(floatx);long double nextupl(long doublex);double nextdown(doublex);float nextdownf(floatx);long double nextdownl(long doublex);

DESCRIPTION        top

       Thenextup(),nextupf(), andnextupl() functions return the next       representable floating-point number greater thanx.       Ifx is the smallest representable negative number in the       corresponding type, these functions return -0.  Ifx is +0 or -0,       the returned value is the smallest representable positive number       of the corresponding type.       Ifx is positive infinity, the returned value is positive       infinity.  Ifx is negative infinity, the returned value is the       largest representable finite negative number of the corresponding       type.       Ifx is NaN, the returned value is NaN.       The value returned bynextdown(x) is-nextup(-x), and similarly       for the other types.

RETURN VALUE        top

       See DESCRIPTION.

ATTRIBUTES        top

       For an explanation of the terms used in this section, seeattributes(7).       ┌──────────────────────────────────────┬───────────────┬─────────┐       │Interface│Attribute│Value│       ├──────────────────────────────────────┼───────────────┼─────────┤       │nextup(),nextupf(),nextupl(),      │ Thread safety │ MT-Safe │       │nextdown(),nextdownf(),nextdownl() │               │         │       └──────────────────────────────────────┴───────────────┴─────────┘

STANDARDS        top

       These functions are described inIEEE Std 754-2008 - Standard forFloating-Point Arithmetic andISO/IEC TS 18661.

HISTORY        top

       glibc 2.24.

SEE ALSO        top

nearbyint(3),nextafter(3)

COLOPHON        top

       This page is part of theman-pages (Linux kernel and C library       user-space interface documentation) project.  Information about       the project can be found at        ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report       for this manual page, see       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.       This page was obtained from the tarball man-pages-6.15.tar.gz       fetched from       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on       2025-08-11.  If you discover any rendering problems in this HTML       version of the page, or you believe there is a better or more up-       to-date source for the page, or you have corrections or       improvements to the information in this COLOPHON (which isnot       part of the original manual page), send a mail to       man-pages@man7.orgLinux man-pages 6.15            2025-05-17nextup(3)

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