copysign3p
Number manipulation function
Usage
#include <math.h>
double copysign(double x, double y); float copysignf(float x, float y); long double copysignl(long double x, long double y);
Prolog
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
Overview
The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1‐2017 defers to the ISO C standard.
These functions shall produce a value with the magnitude of x and the sign of y. On implementations that represent a signed zero but do not treat negative zero consistently in arithmetic operations, these functions regard the sign of zero as positive.
Return value
Upon successful completion, these functions shall return a value with the magnitude of x and the sign of y.
Errors
No errors are defined.
The following sections are informative.
Examples
None.
Application usage
None.
Rationale
None.
Future directions
None.