man3/csqrt.3

   1 '\" t
   2 .\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
   3 .\"
   4 .\" SPDX-License-Identifier: GPL-1.0-or-later
   5 .\"
   6 .TH csqrt 3 (date) "Linux man-pages (unreleased)"
   7 .SH NAME
   8 csqrt, csqrtf, csqrtl \- complex square root
   9 .SH LIBRARY
  10 Math library
  11 .RI ( libm ", " \-lm )
  12 .SH SYNOPSIS
  13 .nf
  14 .B #include <complex.h>
  15 .PP
  16 .BI "double complex csqrt(double complex " z );
  17 .BI "float complex csqrtf(float complex " z );
  18 .BI "long double complex csqrtl(long double complex " z );
  19 .fi
  20 .SH DESCRIPTION
  21 These functions calculate the complex square root of
  22 .IR z ,
  23 with a branch cut along the negative real axis.
  24 (That means that \fIcsqrt(\-1+eps*I)\fP will be close to I while
  25 \fIcsqrt(\-1\-eps*I)\fP will be close to \-I, \fIif eps\fP is a small positive
  26 real number.)
  27 .SH ATTRIBUTES
  28 For an explanation of the terms used in this section, see
  29 .BR attributes (7).
  30 .ad l
  31 .nh
  32 .TS
  33 allbox;
  34 lbx lb lb
  35 l l l.
  36 Interface       Attribute       Value
  37 T{
  38 .BR csqrt (),
  39 .BR csqrtf (),
  40 .BR csqrtl ()
  41 T}      Thread safety   MT-Safe
  42 .TE
  43 .hy
  44 .ad
  45 .sp 1
  46 .SH STANDARDS
  47 C11, POSIX.1-2008.
  48 .SH HISTORY
  49 glibc 2.1.
  50 C99, POSIX.1-2001.
  51 .SH SEE ALSO
  52 .BR cabs (3),
  53 .BR cexp (3),
  54 .BR complex (7)