Manpages - nextup.3

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

  #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.

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.

See DESCRIPTION.

These functions first appeared in glibc in version 2.24.

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

These functions are described in IEEE Std 754-2008 - Standard for Floating-Point Arithmetic and ISO/IEC TS 18661.

*nearbyint*(3), *nextafter*(3)

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