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Common mathematical functions
Functions
Basic operations
(C99)
(C99)
(C99)
(C99)
(C99)
(C99)(C99)(C99)
Exponential functions
(C99)
(C99)
log
(C99)
(C99)
Power functions
(C99)
(C99)
Trigonometric and hyperbolic functions
(C99)
(C99)
(C99)
Error and gamma functions
(C99)
(C99)
(C99)
(C99)
Nearest integer floating point operations
(C99)(C99)(C99)
(C99)
(C99)(C99)(C99)
Floating point manipulation functions
(C99)(C99)
(C99)
(C99)
Classification
(C99)
(C99)
(C99)
Macro constants
 
Defined in header <math.h>
float       logf( float arg );
(since C99)
double      log( double arg );
long double logl( long double arg );
(since C99)

Computes the natural (base e) logarithm of arg.

Contents

Parameters

arg - floating point value

Return value

Natural logarithm of 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.

Example

See also

(C99)(C99)
computes e raised to the given power (ex)
(function) [edit]
computes common (base-10) logarithm (log10(x))
(function) [edit]
(C99)(C99)
computes a number raised to the given power (xy)
(function) [edit]