Calculates the absolute value of a complex number.

double _cabs(   
   struct _complex z   
);  

z
Complex number.

_cabs returns the absolute value of its argument if successful. On overflow, _cabs returns HUGE_VAL and sets errno to ERANGE. You can change error handling with _matherr.

The _cabs function calculates the absolute value of a complex number, which must be a structure of type _complex. The structure z is composed of a real component x and an imaginary component y. A call to _cabs produces a value equivalent to that of the expression sqrt( z.x * z.x + z.y * z.y ).

For more compatibility information, see Compatibility in the Introduction.

// crt_cabs.c  
/* Using _cabs, this program calculates  
 * the absolute value of a complex number.  
 */  
#include <math.h>  
#include <stdio.h>  
  
int main( void )  
{  
   struct _complex number = { 3.0, 4.0 };  
   double d;  
  
   d = _cabs( number );  
   printf( "The absolute value of %f + %fi is %f\n",  
           number.x, number.y, d );  
}  

The absolute value of 3.000000 + 4.000000i is 5.000000  

Floating-Point Support
abs, labs, llabs, _abs64
fabs, fabsf, fabsl