labs

    #include <stdlib.h>
    long int labs(long int x);

computes the absolute value of a long integer

returns the absolute value of a number
the case of a negative number the sign is reversed, a positive number is returned unchanged.
labs is functionally equivalent to abs (), but uses the data type long int

#include <stdio.h> /* including standard library */
//#include <windows.h> /* uncomment this for Windows */
 /* for printf */
#include <stdlib.h>
 
int main( void )
{
  long int i = -42;
  printf("labs from i = %li\n", labs(i));
  return 0;
}

  user@host:~/code-reference.com# ./labs 
  labs from i = 42