CLOG(3) | Linux Programmer's Manual | CLOG(3) |

# 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*

**);**

*-lm*.

# DESCRIPTION

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.# CONFORMING TO

C99.# SEE ALSO

**cabs**(3),

**cexp**(3),

**clog10**(3),

**clog2**(3),

**complex**(7)

# COLOPHON

This page is part of release 3.53 of the Linux*man-pages*project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.

2008-08-11 |