CLOG
Section: Linux Programmer's Manual (3)
Updated: 2017-09-15
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 | MT-Safe
|
CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.
SEE ALSO
cabs(3),
cexp(3),
clog10(3),
clog2(3),
complex(7)
COLOPHON
This page is part of release 5.10 of the Linux
man-pages
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/man-pages/.