@c ----------------------------------------------------------------------
@node log1p, math
@subheading Syntax

@example
#include <math.h>

double log1p(double x);
@end example

@subheading Description

This function computes the natural logarithm of @math{1 + @var{x}}.  It
is more accurate than @samp{log(1 + @var{x})} for small values of
@var{x}.

@subheading Return Value

The natural logarithm of @math{1 + @var{x}}.  If @var{x} is -1, a
negative infinity is returned and @code{errno} is set to @code{ERANGE}.
If @var{x} is less than -1 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