man3/csqrt.3

   1 .\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
   2 .\"
   3 .\" SPDX-License-Identifier: GPL-1.0-or-later
   4 .\"
   5 .TH csqrt 3 (date) "Linux man-pages (unreleased)"
   6 .SH NAME
   7 csqrt, csqrtf, csqrtl \- complex square root
   8 .SH LIBRARY
   9 Math library
  10 .RI ( libm ", " \-lm )
  11 .SH SYNOPSIS
  12 .nf
  13 .B #include <complex.h>
  14 .PP
  15 .BI "double complex csqrt(double complex " z );
  16 .BI "float complex csqrtf(float complex " z );
  17 .BI "long double complex csqrtl(long double complex " z );
  18 .fi
  19 .SH DESCRIPTION
  20 These functions calculate the complex square root of
  21 .IR z ,
  22 with a branch cut along the negative real axis.
  23 (That means that \fIcsqrt(\-1+eps*I)\fP will be close to I while
  24 \fIcsqrt(\-1\-eps*I)\fP will be close to \-I, \fIif eps\fP is a small positive
  25 real number.)
  26 .SH VERSIONS
  27 These functions first appeared in glibc in version 2.1.
  28 .SH ATTRIBUTES
  29 For an explanation of the terms used in this section, see
  30 .BR attributes (7).
  31 .ad l
  32 .nh
  33 .TS
  34 allbox;
  35 lbx lb lb
  36 l l l.
  37 Interface       Attribute       Value
  38 T{
  39 .BR csqrt (),
  40 .BR csqrtf (),
  41 .BR csqrtl ()
  42 T}      Thread safety   MT-Safe
  43 .TE
  44 .hy
  45 .ad
  46 .sp 1
  47 .SH STANDARDS
  48 C99, POSIX.1-2001, POSIX.1-2008.
  49 .SH SEE ALSO
  50 .BR cabs (3),
  51 .BR cexp (3),
  52 .BR complex (7)