ultrix man page for cabs

hypot(3m)																 hypot(3m)

Name
       hypot, cabs - Euclidean distance, complex absolute value

Syntax
       #include <math.h>

       double hypot(x,y)
       double x,y;

       float fhypot(float x, float y)

       double cabs(z)
       struct {double x,y;} z;

       float fcabs(z)
       struct {float x,y;} z;

Description
       The and functions return the following:
       sqrt(x*x+y*y)
       This computation prevents underflows and overflows only if the final result dictates it.

       The functions and are equivalent to the and function with the exception of float data type.

   Error
       When  rounding  off,  for  example, below 0.97 ulps.  Consequently (5.0,12.0) = 13.0 exactly; in general, and return an integer whenever an
       integer might be expected.

       The same cannot be said for the shorter and faster version of and that is provided in the comments in cabs.c;  its  error  can  exceed  1.2
       ulps.

Return Values
       If the correct value overflows, and return HUGE_VAL.   If x or y is NaN, then NaN is returned.

See Also
       math(3m), sqrt(3m)

								       RISC								 hypot(3m)