NAME

log1p - compute a natural logarithm

SYNOPSIS

#include <math.h>

double log1p (double x);

DESCRIPTION

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

RETURN VALUE

Upon successful completion, log1p() returns the natural logarithm of 1.0 + x.

If x is NaN, log1p() returns NaN and may set errno to [EDOM].

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].

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:

[EDOM]

The value of x is NaN.

[ERANGE]

The value of x is -1.0.

No other errors will occur.

EXAMPLES

None.

APPLICATION USAGE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

log(), <math.h>.