clog(3)                    Library Functions Manual                    clog(3)

NAME
       clog, clogf, clogl - natural logarithm of a complex number

LIBRARY
       Math library (libm, -lm)

SYNOPSIS
       #include <complex.h>

       double complex clog(double complex z);
       float complex clogf(float complex z);
       long double complex clogl(long double complex z);

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.

ATTRIBUTES
       For an explanation of the terms used in this section, see
       attributes(7).

       +--------------------------------------------+---------------+---------+
       |Interface                                   | Attribute     | Value   |
       +--------------------------------------------+---------------+---------+
       |clog (), clogf (), clogl ()                 | Thread safety | MT-Safe |
       +--------------------------------------------+---------------+---------+
STANDARDS
       C11, POSIX.1-2008.

HISTORY
       glibc 2.1.  C99, POSIX.1-2001.

SEE ALSO
       cabs(3), cexp(3), clog10(3), clog2(3), complex(7)

Linux man-pages 6.7               2023-10-31                           clog(3)