HP-UX Reference (11i v1 05/09) - 3 Library Functions A-M (vol 6)

copysign(3M) copysign(3M)

NAME

copysign(), copysignf() - copysign functions

SYNOPSIS

#include <math.h>

double copysign(double x, double y);

float copysignf(float x, float y);

DESCRIPTION

The copysign() function returns x with its sign changed to the sign of y.

The

copysign() function is recommended by the IEEE-754 standard for ﬂoating-point arithmetic. The

ISO/ANSI C committee has approved the

copysign() function for inclusion in the C9X draft standard.

copysignf() is a float version of copysign()

; it takes float arguments and returns a float

result.

copysignf() is not speciﬁed by any standard, but it is named in accordance with the conventions

speciﬁed in the "Future Library Directions" section of the ANSI C standard.

To use these functions, compile either with the default -Ae option or with the -Aa

and

-D_HPUX_SOURCE options. Make sure your program includes <

math.h>. Link in the math library by

specifying

-lm on the compiler or linker command line.

RETURN VALUE

The copysign() function returns a value with the magnitude of x and the sign of y.

ERRORS

No errors are deﬁned.