IOINIT(3F)          UNIX Programmer's Manual           IOINIT(3F)

NAME
     ioinit - change f77 I/O initialization

SYNOPSIS
     logical function ioinit (cctl, bzro, apnd, prefix, vrbose)
     logical cctl, bzro, apnd, vrbose
     character*(*) prefix

DESCRIPTION
     This routine will initialize several global parameters in
     the f77 I/O system, and attach externally defined files to
     logical units at run time.  The effect of the flag arguments
     applies to logical units opened after _i_o_i_n_i_t is called.  The
     exception is the preassigned units, 5 and 6, to which _c_c_t_l
     and _b_z_r_o will apply at any time.  _I_o_i_n_i_t is written in
     Fortran-77.

     By default, carriage control is not recognized on any logi-
     cal unit. If _c_c_t_l is .true. then carriage control will be
     recognized on formatted output to all logical units except
     unit 0, the diagnostic channel.  Otherwise the default will
     be restored.

     By default, trailing and embedded blanks in input data
     fields are ignored. If _b_z_r_o is .true. then such blanks will
     be treated as zero's.  Otherwise the default will be
     restored.

     By default, all files opened for sequential access are posi-
     tioned at their beginning.  It is sometimes necessary or
     convenient to open at the END-OF-FILE so that a write will
     append to the existing data.  If _a_p_n_d is .true. then files
     opened subsequently on any logical unit will be positioned
     at their end upon opening.  A value of .false. will restore
     the default behavior.

     Many systems provide an automatic association of global
     names with fortran logical units when a program is run.
     There is no such automatic association in f77.  However, if
     the argument _p_r_e_f_i_x is a non-blank string, then names of the
     form prefixNN will be sought in the program environment. The
     value associated with each such name found will be used to
     open logical unit NN for formatted sequential access.  For
     example, if f77 program _m_y_p_r_o_g_r_a_m included the call

          call ioinit (.true., .false., .false., 'FORT', .false.)

     then when the following sequence

           % setenv FORT01 mydata
           % setenv FORT12 myresults
           % myprogram

Printed 7/31/83                                                 1

IOINIT(3F)          UNIX Programmer's Manual           IOINIT(3F)

     would result in logical unit 1 opened to file _m_y_d_a_t_a and
     logical unit 12 opened to file _m_y_r_e_s_u_l_t_s.  Both files would
     be positioned at their beginning.  Any formatted output
     would have column 1 removed and interpreted as carriage con-
     trol.  Embedded and trailing blanks would be ignored on
     input.

     If the argument _v_r_b_o_s_e is .true. then _i_o_i_n_i_t will report on
     its activity.

     The effect of

          call ioinit (.true., .true., .false., '', .false.)

     can be achieved without the actual call by including
     ``-lI66'' on the _f_7_7 command line.  This gives carriage con-
     trol on all logical units except 0, causes files to be
     opened at their beginning, and causes blanks to be inter-
     preted as zero's.

     The internal flags are stored in a labeled common block with
     the following definition:

          integer*2 ieof, ictl, ibzr
          common /ioiflg/ ieof, ictl, ibzr

FILES
     /usr/lib/libI77.a       f77 I/O library
     /usr/lib/libI66.a       sets older fortran I/O modes

SEE ALSO
     getarg(3F), getenv(3F), ``Introduction to the f77 I/O
     Library''

BUGS
     _P_r_e_f_i_x can be no longer than 30 characters.  A pathname
     associated with an environment name can be no longer than
     255 characters.

     The ``+'' carriage control does not work.

Printed 7/31/83                                                 2