log1p(3M)

NAME

     log1p - compute natural logarithm

SYNOPSIS

     cc [ flag ... ] file ... -lm [ library ... ]
     #include <math.h>

     double log1p(double x);

DESCRIPTION

     The log1p() function computes loge(1.0 + x). The value of  x
     must be greater than -1.0.

RETURN VALUES

     Upon successful completion, log1p() returns the natural log-
     arithm of 1.0 + x.

     If x is NaN, log1p() returns NaN.

     If x is less than -1.0, log1p() returns -HUGE_VAL or NaN and
     sets errno to EDOM.

     If x is  -1.0, log1p() returns -HUGE_VAL and may  set  errno
     to ERANGE.

     For exceptional cases, matherr(3M) tabulates the  values  to
     be returned as dictated by Standards other than XPG4.

ERRORS

     The log1p() function will fail if:

     EDOM  The value of x is less than -1.0.

     The log1p() function may fail and set errno to:

     ERANGE
           The value of x is -1.0.

ATTRIBUTES

     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|

SEE ALSO

     log(3M), matherr(3M), attributes(5), standards(5)