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Retrieves the natural logarithm of a complex number, with a branch cut along the negative real axis.
Syntax
_Dcomplex clog(
_Dcomplex z
);
_Fcomplex clog(
_Fcomplex z
); // C++ only
_Lcomplex clog(
_Lcomplex z
); // C++ only
_Fcomplex clogf(
_Fcomplex z
);
_Lcomplex clogl(
_Lcomplex z
);
Parameters
z
The base of the logarithm.
Return value
The natural logarithm of z. The result is unbounded along the real axis and in the interval [-iπ, +iπ] along the imaginary axis.
The possible return values are:
z parameter |
Return value |
|---|---|
| Positive | The logarithm (base 10) of z |
| Zero | - INF |
| Negative | NaN |
| NaN | NaN |
| + INF | + INF |
Remarks
Because C++ allows overloading, you can call overloads of clog that take and return _Fcomplex and _Lcomplex values. In a C program, clog always takes and returns a _Dcomplex value.
Requirements
| Routine | C header | C++ header |
|---|---|---|
clog, clogf, clogl |
<complex.h> | <ccomplex> |
For more compatibility information, see Compatibility.
See also
Alphabetical function reference
cexp, cexpf, cexpl
cpow, cpowf, cpowl
clog10, clog10f, clog10l