DragonFly On-Line Manual Pages

LOG(3)		      DragonFly Library Functions Manual		LOG(3)

NAME
     log, logf, logl, log10, log10f, log2, log2f, log1p, log1pf -- logarithm
     functions

LIBRARY
     Math Library (libm, -lm)

SYNOPSIS
     #include <math.h>

     double
     log(double x);

     float
     logf(float x);

     double
     log10(double x);

     float
     log10f(float x);

     double
     log2(double x);

     float
     log2f(float x);

     double
     log1p(double x);

     float
     log1pf(float x);

DESCRIPTION
     The log() and logf() functions compute the natural logarithm of x.

     The log10() and log10f() functions compute the logarithm base 10 of x,
     while log2() and log2f() compute the logarithm base 2 of x.

     The log1p() and log1pf() functions compute the natural logarithm of 1 +
     x.  Computing the natural logarithm as log1p(x) is more accurate than
     computing it as log(1 + x) when x is close to zero.

RETURN VALUES
     These functions return the requested logarithm; the logarithm of 1 is +0.
     An attempt to take the logarithm of +-0 results in a divide-by-zero
     exception, and -infinity is returned.  Otherwise, attempting to take the
     logarithm of a negative number results in an invalid exception and a
     return value of NaN.

SEE ALSO
     exp(3), ilogb(3), math(3), pow(3)

STANDARDS
     The log(), logf(), log10(), log10f(), log2(), log2f(), log1p(), and
     log1pf() functions conform to ISO/IEC 9899:1999 (``ISO C99'').

DragonFly 3.5		       December 21, 2011		 DragonFly 3.5