'\" t .\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de) .\" .\" SPDX-License-Identifier: GPL-1.0-or-later .\" .TH csqrt 3 2024-05-02 "Linux man-pages 6.9.1" .SH NAME csqrt, csqrtf, csqrtl \- complex square root .SH LIBRARY Math library .RI ( libm ", " \-lm ) .SH SYNOPSIS .nf .B #include .P .BI "double complex csqrt(double complex " z ); .BI "float complex csqrtf(float complex " z ); .BI "long double complex csqrtl(long double complex " z ); .fi .SH DESCRIPTION These functions calculate the complex square root of .IR z , with a branch cut along the negative real axis. (That means that \fIcsqrt(\-1+eps*I)\fP will be close to I while \fIcsqrt(\-1\-eps*I)\fP will be close to \-I, \fIif eps\fP is a small positive real number.) .SH ATTRIBUTES For an explanation of the terms used in this section, see .BR attributes (7). .TS allbox; lbx lb lb l l l. Interface Attribute Value T{ .na .nh .BR csqrt (), .BR csqrtf (), .BR csqrtl () T} Thread safety MT-Safe .TE .SH STANDARDS C11, POSIX.1-2008. .SH HISTORY glibc 2.1. C99, POSIX.1-2001. .SH SEE ALSO .BR cabs (3), .BR cexp (3), .BR complex (7)