Version 2 of Managing Fortran programs

Arjen Markus This page is meant to elaborate the management of interactive For tran programs via Tcl.

Note: Very sketchy right now - I want to get the information available

Below is a simple example:

Tcl asks for a string and puts it to an executable program written in Fortran.
This program reads the string and writes it out, until the string is "q", then it exits.
At this moment, Tcl must exit too.

The trick is to use file events to handle the buffering and broken pipe issues correctly and to use the non-standard Fortran routine flush() to flush the output buffers.

The Tcl code:

   global inout
   set inout [open "|copy_inp" "w+"]
   fconfigure $inout -buffering none

   puts "Input:"
   fileevent $inout readable {
      gets $::inout copied
      puts $copied
      if { [eof $inout] } { close $inout; set forever 1 }
   }
   fileevent stdin readable {
      gets stdin line
      puts $::inout $line
      puts "Input:"
   }
   vwait forever

The Fortran code:

   !  copy_inp.f90 --
   !     Copy stdin to stdout - IPC test
   !
   program copy_inp
      ! Compaq Visual Fortran requires:
      ! use dflib

      character(len=60) :: string

      do
         read(*,*)  string
         write(*,*) 'Copied: ', string
         call flush( 6 )

         ! On SGI use:
         ! call flush( 101 )

         if ( string .eq. 'q' ) stop
      enddo
   end program

Notes:

Standard output is usually unit 6, but on SGI it is unit 101
As FLUSH() is non-standard, you may need to add a USE statement, or link with a special library

See also: open, exec, Inventory of IPC methods