log10
From cppreference.com
                    
                                        
                    
                    
                                                            
                    |   Defined in header  
<math.h>
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|   float       log10f( float arg ); 
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(since C99) | |
|   double      log10( double arg ); 
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|   long double log10l( long double arg ); 
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(since C99) | |
Computes the common (base 10) logarithm of arg.
[edit] Parameters
| arg | - | floating point value | 
[edit] Return value
Base 10 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. 
[edit] See also
|    computes natural (base e) logarithm (to base e) (ln(x))   (function)  | 
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|    raises a number to the given power (xy)   (function)  | 
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