Interfacing Python With Fortran through Command-Line Using Pexpect

I am using pexpect with python to create a program that allows a user to interact with a FORTRAN program through a website. From the FORTRAN program I am receive the error:

open: Permission denied apparent state: unit 4 named subsat.out.55 last format: list io lately writing sequential formatted external IO 55

when I attempt to:

p = pexpect开发者_如何学C.spawn(myFortranProgram,[],5)
p.logfile_read = sys.stdout
p.expect("(.*)")
p.sendline("55")

From what I understand, I am likely sending the 55 to the wrong input unit. How do I correctly send input to a FORTRAN program using pexpect in Python?

Thank You.

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Edit: When p.sendline's parameter is empty (e.g. p.sendline()) or only contains spaces, the program proceeds as expected. In sending non-space values to a FORTRAN program, do I need to specify the input format somehow?

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The pexpect module is something I'd not used before, but could be useful to me, so I tried this.

Edit:

I've not been able to duplicate the error you're reporting. Looking at this error leads me to believe that it has something to do with reading from a file, which may be a result of other issues. From what I've seen, this isn't what pexpect is designed to handle directly; however, you may be able to make it work with a pipe, like the example in my original answer, below.

I'm having no problem sending data to Fortran's I/O stream 5 (stdin). I created a Fortran program called regurgitate which issues a " Your entry? " prompt, then gets a line of input from the user on I/O stream 5, then prints it back out. The following code works with that program:

import pexpect
child = pexpect.spawn('./regurgitate')
child.setecho(False)
ndx = child.expect('.*Your entry?.*')
child.sendline('42')
child.expect([pexpect.EOF])
print child.before
child.close()

The output is simply:

42

Exactly what I expected. However, if my Fortran program says something different (such as "Your input?"), the pexpect just hangs or times out.

Original suggestion:

Maybe this pexpect.run() sample will help you. At least it seems to run my regurgitate program (a simple Fortran program that accepts an input and then prints it out):

import pexpect
out = pexpect.run('/bin/bash -c "/bin/cat forty-two | ./regurgitate"')
print out

The output was:

Your entry?
42

Where regurgitate prints out a "Your entry?" prompt and the forty-two file contains "42" (without quotes in both cases).