@c ---------------------------------------------------------------------- @node log10, math @subheading Syntax @example #include double log10(double x); @end example @subheading Description This function computes the base-10 logarithm of @var{x}. @subheading Return Value The logarithm base 10 of @var{x}. If @var{x} is zero, a negative infinity is returned and @code{errno} is set to @code{ERANGE}. If @var{x} is negative or @code{+Inf} or a @code{NaN}, the return value is @code{NaN} and @code{errno} is set to @code{EDOM}. @subheading Portability @portability ansi, posix