nextdownf(3) - BetterMan

nextdownf(3)

return next floating-point number toward positive/negative infinity

distropkg manpages-dev@6.9.1-1dataset 2026-04-01T06:19:02Z+debian+ec4110e+mandoc:1.14.6-4

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
);

—

NAME

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

SYNOPSIS

bash

#define _GNU_SOURCE\n     /* See feature_test_macros(7) */
\n#include <math.h>

bash

double nextup(double \nx\n);\n
\nfloat nextupf(float \nx\n);\n
\nlong double nextupl(long double \nx\n);

bash

double nextdown(double \nx\n);\n
\nfloat nextdownf(float \nx\n);\n
\nlong double nextdownl(long double \nx\n);

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.