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  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(),      │ Thread safety │ MT-Safe │
       │nextdown(), nextdownf(), nextdownl() │               │         │
       └─────────────────────────────────────┴───────────────┴─────────┘

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

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