COPYSIGN(3) | Library Functions Manual | COPYSIGN(3)

# NAME

`copysign`, `copysignf`, `copysignl` —
functions to manipulate signs

# LIBRARY

Math Library (libm, -lm)

# SYNOPSIS

`#include <math.h>`

double
`copysign`(double x, double y);

float
`copysignf`(float x, float y);

long double
`copysignl`(long double x, long double y);

`#include <tgmath.h>`

real-floating
`copysign`(real-floating x, real-floating y);

# DESCRIPTION

The `copysign`(), `copysignf`(), and `copysignl`() functions return a value whose absolute value matches x, but whose sign bit is taken from y.

# RETURN VALUES

Upon successful completion, all three functions return a value with the magnitude of x and the sign of y. If x is NaN , the functions return a NaN with the sign of y.

# SEE ALSO

math(3), signbit(3)

# STANDARDS

The described functions conform to ISO/IEC 9899:1999 (“ISO C99”).

# CAVEATS

Note that on implementations that represent a signed zero but do not treat negative zero consistently in arithmetic operations, these functions may regard the sign of zero as positive.

September 28, 2017 | NetBSD 9.5