fabs(), fabsf()

Compute the absolute value of a double number

Synopsis:

#include <math.h>

double fabs( double x );

float fabsf( float x );

Arguments:

x: The number you want the absolute value of.

Library:

libm

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

Description:

These functions compute the absolute value of x.

Returns:

The absolute value of x.

Note: If an error occurs, these functions return 0, but this is also a valid mathematical result. If you want to check for errors, set errno to 0, call the function, and then check errno again. These functions don't change errno if no errors occurred.

Examples:

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

int main( void )
{
    printf( "%f %f\n", fabs(.5), fabs(-.5) );
    return EXIT_SUCCESS;
}

produces the output:

0.500000 0.500000

Classification:

ANSI, POSIX 1003.1

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