ioinit(3f) [bsd man page]

IOINIT(3F)																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 ioinit is called.	The exception is the preassigned units,  5
       and 6, to which cctl and bzro will apply at any time.  Ioinit is written in Fortran-77.

       By  default, carriage control is not recognized on any logical unit. If cctl is .true.  then carriage control will be recognized on format-
       ted 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 bzro is .true.  then such blanks will be  treated	as  zeros.
       Otherwise the default will be restored.

       By  default,  all files opened for sequential access are positioned 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 apnd 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.

       Ioinit  may  be	used to associate file names with Fortran logical unit numbers through environment variables (see "Introduction to the f77
       I/O Library" for a more general way of doing this).  If the argument prefix 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 myprogram included the call

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

       then when the following sequence

	     % setenv FORT01 mydata
	     % setenv FORT12 myresults
	     % myprogram

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

       If the argument vrbose is .true.  then ioinit 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 f77 command line.	This gives carriage control on all  logical  units
       except 0, causes files to be opened at their beginning, and causes blanks to be interpreted 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

       Prefix 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.

4.2 Berkeley Distribution					   May 27, 1986 							IOINIT(3F)

TOPEN(3F)																 TOPEN(3F)

NAME

       topen, tclose, tread, twrite, trewin, tskipf, tstate - f77 tape I/O

SYNOPSIS

       integer function topen (tlu, devnam, label)
       integer tlu
       character*(*) devnam
       logical label

       integer function tclose (tlu)
       integer tlu

       integer function tread (tlu, buffer)
       integer tlu
       character*(*) buffer

       integer function twrite (tlu, buffer)
       integer tlu
       character*(*) buffer

       integer function trewin (tlu)
       integer tlu

       integer function tskipf (tlu, nfiles, nrecs)
       integer tlu, nfiles, nrecs

       integer function tstate (tlu, fileno, recno, errf, eoff, eotf, tcsr)
       integer tlu, fileno, recno, tcsr
       logical errf, eoff, eotf

DESCRIPTION

       These functions provide a simple interface between f77 and magnetic tape devices.  A ``tape logical unit'', tlu, is ``topen''ed in much the
       same way as a normal f77 logical unit is ``open''ed.  All other operations are performed via the tlu.  The tlu has no relationship  at  all
       to any normal f77 logical unit.

       Topen  associates  a device name with a tlu.  Tlu must be in the range 0 to 3.  The logical argument label should indicate whether the tape
       includes a tape label.  This is used by trewin below.  Topen does not move the tape.  The normal returned value is 0.  If the value of  the
       function is negative, an error has occured.  See perror(3F) for details.

       Tclose closes the tape device channel and removes its association with tlu.  The normal returned value is 0.  A negative value indicates an
       error.

       Tread reads the next physical record from tape to buffer.  Buffer must be of type character.  The size of buffer should be large enough	to
       hold  the largest physical record to be read.  The actual number of bytes read will be returned as the value of the function.  If the value
       is 0, the end-of-file has been detected.  A negative value indicates an error.

       Twrite writes a physical record to tape from buffer.  The physical record length will be the size of buffer.  Buffer must be of type  char-
       acter.  The number of bytes written will be returned.  A value of 0 or negative indicates an error.

       Trewin rewinds the tape associated with tlu to the beginning of the first data file.  If the tape is a labelled tape (see topen above) then
       the label is skipped over after rewinding.  The normal returned value is 0.  A negative value indicates an error.

       Tskipf allows the user to skip over files and/or records.  First, nfiles end-of-file marks are skipped. If the current file is at EOF, this
       counts  as 1 file to skip.  (Note: This is the way to reset the EOF status for a tlu.)  Next, nrecs physical records are skipped over.  The
       normal returned value is 0.  A negative value indicates an error.

       Finally, tstate allows the user to determine the logical state of the tape I/O channel and to see the tape drive control  status  register.
       The  values  of fileno and recno will be returned and indicate the current file and record number.  The logical values errf, eoff, and eotf
       indicate an error has occurred, the current file is at EOF, or the tape has reached logical end-of-tape.  End-of-tape (EOT) is indicated by
       an  empty  file, often referred to as a double EOF mark.  It is not allowed to read past EOT although it is allowed to write.  The value of
       tcsr will reflect the tape drive control status register.  See ht(4) for details.

FILES

       /usr/lib/libU77.a

SEE ALSO

       ht(4), perror(3F), rewind(1)

4.2 Berkeley Distribution					   May 15, 1985 							 TOPEN(3F)