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 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 bzro is .true.  then such blanks will be treated as zeroes.  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. 

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 the UNIX f77(1) compiler.  However, if the argument prefix is a nonblank 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 or formatted sequential access.  For example, if the FORTRAN 77 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 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 FORTRAN 77 I/O library

SEE ALSO

getarg(3F), getenv(3F)

FORTRAN Programmer’s Guide

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. 

Sun Release 3.2  —  Last change: 17 July 1986