cabs

#include <math.h>

char cabs (
  char val);     /* number to take absolute value of */

The cabs function determines the absolute value of the character val.

The cabs function returns the absolute value of val.

abs, fabs, labs

#include <math.h>
#include <stdio.h> /* for printf */

void tst_cabs (void) {
  char x;
  char y;

  x = -23;
  y = cabs (x);

  printf ("CABS(%bd) = %bd\n", x, y);
}