NEXTUP(3)                  Linux Programmer's Manual                 NEXTUP(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(double x);
       float nextupf(float x);
       long double nextupl(long double x);

       double nextdown(double x);
       float nextdownf(float x);
       long double nextdownl(long double x);

       Link with -lm.

DESCRIPTION
       The nextup(), nextupf(), and nextupl() functions return the next repre-
       sentable 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).

       allbox; lbw36 lb lb l l l.  Interface Attribute Value T{ nextup(), nex-
       tupf(), nextupl(),
       nextdown(), nextdownf(), nextdownl() T}   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)

COLOPHON
       This  page  is  part of release 4.16 of the Linux man-pages project.  A
       description of the project, information about reporting bugs,  and  the
       latest     version     of     this    page,    can    be    found    at
       https://www.kernel.org/doc/man-pages/.



GNU                               2017-09-15                         NEXTUP(3)