Returns a value that has the magnitude of one argument and the sign of another.

double copysign(   
   double x,  
   double y   
);  
float copysign(   
   float x,  
   float y   
); // C++ only  
long double copysign(   
   long double x,  
   long double y   
); // C++ only  
float copysignf(   
   float x,  
   float y   
); // C++ only  
long double copysignl(   
   long double x,  
   long double y   
); // C++ only  
double _copysign(   
   double x,  
   double y   
);  
long double _copysignl(   
   long double x,  
   long double y   
);  

x
The floating-point value that's returned as the magnitude of the result.

y
The floating-point value that's returned as the sign of the result.

Floating-Point Support Routines

The copysign functions return a floating-point value that combines the magnitude of x and the sign of y. There is no error return.

Because C++ allows overloading, you can call overloads of copysign that take and return float or long double values. In a C program, copysign always takes and returns a double.

For more compatibility information, see Compatibility.

fabs, fabsf, fabsl
_chgsign, _chgsignf, _chgsignl