# cabsf(3) [freebsd man page]

```HYPOT(3)						   BSD Library Functions Manual 						  HYPOT(3)

NAME
hypot, hypotf, hypotl, cabs, cabsf, cabsl -- Euclidean distance and complex absolute value functions

LIBRARY
Math Library (libm, -lm)

SYNOPSIS
#include <math.h>

double
hypot(double x, double y);

float
hypotf(float x, float y);

long double
hypotl(long double x, long double y);

#include <complex.h>

double
cabs(double complex z);

float
cabsf(float complex z);

long double
cabsl(long double complex z);

DESCRIPTION
The hypot(), hypotf() and hypotl() functions compute the sqrt(x*x+y*y) in such a way that underflow will not happen, and overflow occurs only
if the final result deserves it.  The cabs(), cabsf() and cabsl() functions compute the complex absolute value of z.

hypot(infinity, v) = hypot(v, infinity) = +infinity for all v, including NaN.

ERROR (due to Roundoff, etc.)
Below 0.97 ulps.  Consequently hypot(5.0, 12.0) = 13.0 exactly; in general, hypot and cabs return an integer whenever an integer might be
expected.

NOTES
As might be expected, hypot(v, NaN) and hypot(NaN, v) are NaN for all finite v.  But programmers might be surprised at first to discover that
hypot(+-infinity, NaN) = +infinity.  This is intentional; it happens because hypot(infinity, v) = +infinity for all v, finite or infinite.
Hence hypot(infinity, v) is independent of v.  Unlike the reserved operand fault on a VAX, the IEEE NaN is designed to disappear when it
turns out to be irrelevant, as it does in hypot(infinity, NaN).

carg(3), math(3), sqrt(3)

STANDARDS
The hypot(), hypotf(), hypotl(), cabs(), cabsf(), and cabsl() functions conform to ISO/IEC 9899:1999 (``ISO C99'').

HISTORY
Both a hypot() function and a cabs() function appeared in Version 7 AT&T UNIX.

BSD								  March 30, 2008							       BSD```

## Check Out this Related Man Page

```HYPOT(3)						   BSD Library Functions Manual 						  HYPOT(3)

NAME
hypot, hypotf -- Euclidean distance and complex absolute value functions

LIBRARY
Math Library (libm, -lm)

SYNOPSIS
#include <math.h>

double
hypot(double x, double y);

float
hypotf(float x, float y);

DESCRIPTION
The hypot() functions compute the sqrt(x*x+y*y) in such a way that underflow will not happen, and overflow occurs only if the final result
deserves it.

hypot(infinity, v) = hypot(v, infinity) = +infinity for all v, including NaN.

ERRORS
Below 0.97 ulps.  Consequently hypot(5.0, 12.0) = 13.0 exactly; in general, hypot returns an integer whenever an integer might be expected.

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

NOTES
As might be expected, hypot(v, NaN) and hypot(NaN, v) are NaN for all finite v; with "reserved operand" in place of "NaN", the same is true
on a VAX.	But programmers on machines other than a VAX (it has no infinity) might be surprised at first to discover that hypot(+-infinity,
NaN) = +infinity.	This is intentional; it happens because hypot(infinity, v) = +infinity for all v, finite or infinite.  Hence
hypot(infinity, v) is independent of v.  Unlike the reserved operand fault on a VAX, the IEEE NaN is designed to disappear when it turns out
to be irrelevant, as it does in hypot(infinity, NaN).