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);
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
x is positive infinity, the returned value is positive
x is negative infinity, the returned value is the
largest representable finite negative number of the corresponding
x is Nan, the returned value is NaN.
The value returned by
and similarly for the other types.
These functions first appeared in glibc in version 2.24.
These functions are described in IEEE Std 754-2008 - Standard for
Floating-Point Arithmetic and
ISO/IEC TS 18661.
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