clog
Section: C Library Functions (3)
Updated: 2022-12-15
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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.
VERSIONS
These functions were added in glibc 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
|
STANDARDS
C99, POSIX.1-2001, POSIX.1-2008.
SEE ALSO
cabs(3),
cexp(3),
clog10(3),
clog2(3),
complex(7)
Index
- NAME
-
- LIBRARY
-
- SYNOPSIS
-
- DESCRIPTION
-
- VERSIONS
-
- ATTRIBUTES
-
- STANDARDS
-
- SEE ALSO
-
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