LOG(3) BSD Library Functions Manual LOG(3)NAME
log, logf, logl, log10, log10f, log1p, log1pf — logarithm functions
Math Library (libm, -lm)
The log() and logf() functions compute the natural logarithm of x.
The log10() and log10f() functions compute the logarithm base 10 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.
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 -∞ is returned. Otherwise, attempting to take the logarithm of
a negative number results in an invalid exception and a return value of
SEE ALSOexp(3), ilogb(3), math(3), pow(3)STANDARDS
The log(), logf(), log10(), log10f(), log1p(), and log1pf() functions
conform to ISO/IEC 9899:1999 (“ISO C99”).
BSD January 17, 2008 BSD