log10(), log10f(), log10l()

Compute the logarithm (base 10) of a number

Synopsis:

#include <math.h>

double log10( double x );

float log10f( float x );

long double log10l( long double x );

Arguments:

x
The number that you want to compute the log of.

Library:

libm

Use the -l m option to qcc to link against this library.

Description:

These functions compute the base 10 logarithm of x:

log10 x

To check for error situations, use feclearexcept() and fetestexcept():

Returns:

The base 10 logarithm of x.

Examples:

#include <stdio.h>
#include <math.h>
#include <fenv.h>
#include <stdlib.h>

int main( void )
{
    int except_flags;

    feclearexcept(FE_ALL_EXCEPT);

    printf( "%f\n", log10(.5) );

    except_flags = fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW);
    if(except_flags) {
        /* An error occurred; handle it appropriately. */
    }

    return EXIT_SUCCESS;
}

produces the output:

-0.301030

Classification:

ANSI, POSIX 1003.1

Safety:  
Cancellation point No
Interrupt handler No
Signal handler No
Thread Yes