CLOG
Section: Linux Programmer's Manual (3)
Updated: 20170915
Page Index
NAME
clog, clogf, clogl  natural logarithm of a complex number
SYNOPSIS
#include <complex.h>
double complex clog(double complex z);
float complex clogf(float complex z);
long double complex clogl(long double complex z);
Link with lm.
DESCRIPTION
These functions calculate the complex natural logarithm of
z,
with a branch cut along the negative real axis.
The logarithm
clog()
is the inverse function of the exponential
cexp(3).
Thus, if y = clog(z), then z = cexp(y).
The imaginary part of
y
is chosen in the interval [pi,pi].
One has:
clog(z) = log(cabs(z)) + I * carg(z)
Note that
z
close to zero will cause an overflow.
VERSIONS
These functions first appeared in glibc in version 2.1.
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
Interface  Attribute  Value

clog(),
clogf(),
clogl()
 Thread safety  MTSafe

CONFORMING TO
C99, POSIX.12001, POSIX.12008.
SEE ALSO
cabs(3),
cexp(3),
clog10(3),
clog2(3),
complex(7)
COLOPHON
This page is part of release 5.10 of the Linux
manpages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
https://www.kernel.org/doc/manpages/.