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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