CSQRT(3)						   BSD Library Functions Manual 						  CSQRT(3)

NAME

     csqrt, csqrtf, csqrtl -- complex square root functions

LIBRARY

     Math Library (libm, -lm)

SYNOPSIS

     #include <complex.h>

     double complex
     csqrt(double complex z);

     float complex
     csqrtf(float complex z);

     long double complex
     csqrtl(long double complex z);

DESCRIPTION

     The csqrt(), csqrtf(), and csqrtl() functions compute the square root of z in the complex plane, with a branch cut along the negative real
     axis.  In other words, csqrt(), csqrtf(), and csqrtl() always return the square root whose real part is non-negative.

RETURN VALUES

     These functions return the requested square root.	The square root of 0 is +0 +- 0, where the imaginary parts of the input and respective
     result have the same sign.  For infinities and NaNs, the following rules apply, with the earlier rules having precedence:

	   Input		Result
	   k + infinity*I	infinity + infinity*I	    (for all k)
	   -infinity + NaN*I	NaN +- infinity*I
	   infinity + NaN*I	infinity + NaN*I
	   k + NaN*I		NaN + NaN*I
	   NaN + k*I		NaN + NaN*I
	   -infinity + k*I	+0 + infinity*I
	   infinity + k*I	infinity + 0*I

     For numbers with negative imaginary parts, the above special cases apply given the identity:
	   csqrt(conj(z) = conj(sqrt(z))
     Note that the sign of NaN is indeterminate.  Also, if the real or imaginary part of the input is finite and an NaN is generated, an invalid
     exception will be thrown.

SEE ALSO

     cabs(3), fenv(3), math(3)

STANDARDS

     The csqrt(), csqrtf(), and csqrtl() functions conform to ISO/IEC 9899:1999 (``ISO C99'').

BUGS

     For csqrt() and csqrtl(), inexact results are not always correctly rounded.

BSD
								  March 30, 2008							       BSD