cc [ flag ... ] file ... -lm [ library ... ] #include <math.h>double log1p(double x);
Upon successful completion, log1p() returns the natural logarithm 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.
The log1p() function will fail if:
The value of x is less than -1.0.
The log1p() function may fail and set errno to:
The value of x is -1.0.
See attributes(5) for descriptions of the following attributes:
|ATTRIBUTE TYPE||ATTRIBUTE VALUE|