clog2, clog2f, clog2l - base-2 logarithm of a complex number

Math library (`libm`

, `-lm`

)

```
#include <complex.h>
double complex clog2(double complex z);
float complex clog2f(float complex z);
long double complex clog2l(long double complex z);
```

The call `clog2(z)`

is equivalent to
`clog(z)/log(2)`

.

The other functions perform the same task for `float`

and
`long double`

.

Note that `z`

close to zero will cause an overflow.

None.

These function names are reserved for future use in C99.

Not yet in glibc, as at glibc 2.19.