Return the logarithm of their arguments.

    Format

      #include  <math.h>

      double log  (double x);

      float logf  (float x); (Integrity servers, Alpha)

      long double logl  (long double x); (Integrity servers, Alpha)

      double log2  (double x); (Integrity servers, Alpha)

      float log2f  (float x); (Integrity servers, Alpha)

      long double log2l  (long double x); (Integrity servers, Alpha)

      double log10  (double x);

      float log10f  (float x); (Integrity servers, Alpha)

      long double log10l  (long double x);
                          (Integrity servers, Alpha)

1  –  Argument

 x

    A real number.

2  –  Description

    The log functions compute the natural (base e) logarithm of x.

    The log2 functions compute the base 2 logarithm of x.

    The log10 functions compute the common (base 10) logarithm of x.

3  –  Return Values

    x                  The logarithm of the argument (in the
                       appropriate base).
    -HUGE_VAL          x is 0 (errno is set to ERANGE), or x is
                       negative (errno is set to EDOM).
    NaN                x is NaN; errno is set to EDOM.