fabs() computes the absolute value of x.

                           Entry-Point Names

    Generic                               Compaq
    Function   Data Type   OpenVMS        Tru64 UNIX
    Name       Required    Alpha          Alpha

    fabs       S_FLOAT     math$fabs_s    fabsf
               T_FLOAT     math$fabs_t    fabs
               X_FLOAT     math$fabs_x    fabsl
               F_FLOAT     math$fabs_f
               G_FLOAT     math$fabs_g