cc [ flags ] -I/usr/local/include file(s) -L/usr/local/lib -lmcw [ ... ] #include <mathcw.h> extern float log21pf (float x); extern double log21p (double x); extern long double log21pl (long double x); extern __float80 log21pw (__float80 x); extern __float128 log21pq (__float128 x); extern long_long_double log21pll (long_long_double x); extern decimal_float log21pdf (decimal_float x); extern decimal_double log21pd (decimal_double x); extern decimal_long_double log21pdl (decimal_long_double x); extern decimal_long_long_double log21pdll (decimal_long_long_double x);
NB: Functions with prototypes containing underscores in type names may be available only with certain extended compilers.
Use this function in preference to log2(1 + x) when the magnitude of x is small, to avoid serious accuracy loss.