log1p, log1pf : log of 1 + x

Synopsis

#include <math.h>
double log1p(double x);
float log1pf(float x);
```### Description

log1p calculates the natural logarithm of 1+x. You can use log1p rather than `log(1+x)' for greater precision when x is very small. log1pf calculates the same thing, but accepts and returns float values rather than double.### Returns

log1p returns a double, the natural log of 1+x. log1pf returns a float, the natural log of 1+x.

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**Authoritative source**: BUSMASTER DITA help source `log1p.dita`, compiled into `BUSMASTER.CHM` with the application.