MALLOC(3F)                                                          MALLOC(3F)



NAME
       malloc, free, falloc - memory allocator

SYNOPSIS
       subroutine malloc (size, addr)
       integer size, addr

       subroutine free (addr)
       integer addr

       subroutine falloc (nelem, elsize, clean, basevec, addr, offset)
       integer nelem, elsize, clean, addr, offset

DESCRIPTION
       _M_a_l_l_o_c, _f_a_l_l_o_c  and  _f_r_e_e  provide  a general-purpose memory allocation
       package.  _M_a_l_l_o_c returns in _a_d_d_r the address of a  block  of  at  least
       _s_i_z_e bytes beginning on an even-byte boundary.

       _F_a_l_l_o_c  allocates  space  for an array of _n_e_l_e_m elements of size _e_l_s_i_z_e
       and returns the address of the block in _a_d_d_r_.  It zeros  the  block  if
       _c_l_e_a_n is 1.  It returns in _o_f_f_s_e_t an index such that the storage may be
       addressed as _b_a_s_e_v_e_c_(_o_f_f_s_e_t_+_1_) _._._. _b_a_s_e_v_e_c_(_o_f_f_s_e_t_+_n_e_l_e_m_)_.  _F_a_l_l_o_c  gets
       extra  bytes  so  that  after  address  arithmetic,  all the objects so
       addressed are within the block.

       The argument to _f_r_e_e is the address of a block previously allocated  by
       _m_a_l_l_o_c  or _f_a_l_l_o_c; this space is made available for further allocation,
       but its contents are left undisturbed.  To  free  blocks  allocated  by
       _f_a_l_l_o_c_, use _a_d_d_r in calls to _f_r_e_e_, do not use _b_a_s_e_v_e_c_(_o_f_f_s_e_t_+_1_)_.

       Needless  to  say,  grave disorder will result if the space assigned by
       _m_a_l_l_o_cor_f_a_l_l_o_c is overrun or if some random number is handed to _f_r_e_e.

DIAGNOSTICS
       _M_a_l_l_o_c and _f_a_l_l_o_c set _a_d_d_r to 0 if there is no available memory  or  if
       the  arena  has been detectably corrupted by storing outside the bounds
       of a block.

       The following example shows how to obtain memory and use  it  within  a
       subprogram:

             integer addr, work(1), offset
                ...
             call falloc ( n, 4, 0, work, addr, offset )
             do 10 i = 1, n
             work(offset+i) = ...
       10    continue

       The  next  example  reads in dimension information, allocates space for
       two arrays and two vectors, and calls subroutine _d_o_i_t to do the  compu‐
       tations:

             integer addr, dummy(1), offs
             read *, k, l, m
             indm1   = 1
             indm2   = indm1 + k*l
             indm3   = indm2 + l*m
             indsym  = indm3 + k*m
             lsym = n*(n+1)/2
             indv  = indsym + lsym
             indtot = indv + m
             call falloc ( indtot, 4, 0, dummy, addr, offs )
             call doit( dummy(indm1+offs), dummy(indm2+offs),
            .           dummy(indm3+offs), dummy(indsym+offs),
            .           dummy(indv +offs), m, n, lsym )
             end
             subroutine doit( arr1, arr2, arr3, vsym, vec, m, n, lsym )
             real arr1(k,l), arr2(l,m), arr3(k,m), vsym(lsym), v2(m)
                ...

FILES
       /usr/lib/libU77.a

SEE ALSO
       malloc(3)



4.3 Berkeley Distribution        May 15, 1985                       MALLOC(3F)