dsfree (2) --- free a block of dynamic storage           01/07/83


            _C_a_l_l_i_n_g _I_n_f_o_r_m_a_t_i_o_n

                 subroutine dsfree (block)
                 pointer block

                 Library:  vswtlb (standard Subsystem library)


            _F_u_n_c_t_i_o_n

                 'Dsfree'  returns a block of storage allocated by 'dsget' to
                 the available space list.  The argument must  be  a  pointer
                 returned by 'dsget'.

                 See  the  remarks  under 'dsget' for required initialization
                 measures.


            _I_m_p_l_e_m_e_n_t_a_t_i_o_n

                 'Dsfree' is an implementation of Algorithm B on page 440  of
                 Volume  1  of  _T_h_e _A_r_t _o_f _C_o_m_p_u_t_e_r _P_r_o_g_r_a_m_m_i_n_g, by Donald E.
                 Knuth.  The reader is referred to that source  for  detailed
                 information.

                 'Dsfree' and 'dsget' maintain a list of free storage blocks,
                 ordered  by address.  'Dsfree' searches the list to find the
                 proper location for the block being  returned,  and  inserts
                 the  block  into  the  list  at that location.  If blocks on
                 either side of the newly-returned block are available,  they
                 are coalesced with the new block.  If the block address does
                 not  correspond  to  the  address  of  any  allocated block,
                 'dsfree' remarks "attempt to  free  unallocated  block"  and
                 waits for the user to type a letter "c" to continue.  If any
                 other character is typed, the program is terminated.


            _C_a_l_l_s

                 getlin, remark


            _B_u_g_s

                 The algorithm itself is not the best.


            _S_e_e _A_l_s_o

                 dsget (2), dsinit (2), dsdump (2), dsdbiu (6)








            dsfree (2)                    - 1 -                    dsfree (2)