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
Colophon
This page is part of release 5.04 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/.
Referenced By
cacos(3), casin(3), catan(3), cexp(3), clog10(3), clog2(3), complex(7), log(3).
The man pages clogf(3) and clogl(3) are aliases of clog(3).