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LOG(3)			     Library Functions Manual			  LOG(3)

NAME
     log,  logf, logl, log10, log10f, log10l, log2, log2f, log2l, log1p, log1pf,
     log1pl -- logarithm functions

LIBRARY
     Math Library (libm, -lm)

SYNOPSIS
     #include <math.h>

     double
     log(double x);

     float
     logf(float x);

     long double
     logl(long double x);

     double
     log10(double x);

     float
     log10f(float x);

     long double
     log10l(long double x);

     double
     log2(double x);

     float
     log2f(float x);

     long double
     log2l(long double x);

     double
     log1p(double x);

     float
     log1pf(float x);

     long double
     log1pl(long double x);

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

     The log10(), log10f(), and log10l() functions compute the logarithm base 10
     of x, while log2(), log2f(), and log2l() compute the logarithm base 2 of x.

     The log1p(), log1pf(), and log1pl() 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 excep-
     tion, and -infinity is returned.  Otherwise, attempting to take  the  loga-
     rithm  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(), logl(), log10(), log10f(),  log10l(),  log2(),	log2f(),
     log2l(),  log1p(),  log1pf(),  and  log1pl()  functions  conform to ISO/IEC
     9899:1999 ("ISO C99").

HISTORY
     The log() function first appeared	in  Version  1	AT&T  UNIX;  log10()  in
     Version 7 AT&T UNIX; log1p() in 4.3BSD.

FreeBSD ports 15.quarterly	 March 22, 2020 			  LOG(3)

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<https://man.freebsd.org/cgi/man.cgi?query=logl&sektion=3&manpath=FreeBSD+15.1-RELEASE+and+Ports.quarterly>

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