##### cppreference.com

##### Search

Create account

##### Namespaces

- Page
- Discussion

##### Variants

##### Views

- View
- Edit
- History

##### Actions

# log1p

From cppreference.com
< c‎ | numeric‎ | math

Defined in header `<math.h>` |  |
float log1pf( float arg ); |  | (since C99)
double log1p( double arg ); |  | (since C99)
long double log1pl( long double arg ); |  | (since C99)

Computes the natural (base e) logarithm of 1+arg. This function is more precise than the expression log(1+arg) if `arg` is close to zero.

### [edit] Parameters

arg | - | floating point value

### [edit] Return value

ln(1+arg)

Domain error occurs if `arg` is negative. NAN is returned in that case.

Range error occurs if `arg` is ​0​. -HUGE_VAL is returned in that case.

### [edit] See also

log | computes natural (base e) logarithm (to base e) (ln(x)) (function) [edit]
log10 | computes common (base 10) logarithm (log10(x)) (function) [edit]
C++ documentation for log1p

Retrieved from "http://en.cppreference.com/mwiki/index.php?title=c/numeric/math/log1p&oldid=62594"