Defined in header
float log2f( float arg );
double log2( double arg );
long double log2l( long double arg );
Computes the base 2 logarithm of arg.
|arg||-||floating point value|
 Return value
Domain error occurs if
arg is negative. NAN is returned in that case.
Range error occurs if
arg is 0. -HUGE_VAL is returned in that case.
 See also
| computes natural (base e) logarithm (to base e) (ln(x)) |
| computes common (base 10) logarithm (log10(x)) |
C++ documentation for log2