Avi Berkovich wrote:
Hello,
I was unable to use popen2.popen4 to grab python.exe's (2.3) output, for starts, it doesn't show the version information at the beginning and won't return anything when writing to the stdin pipe, it seems that if I give it some error nous expression, the pipe would return the exception data, though nothing else comes through.
A friend of mine also tried this using win32api on delphi, and got the same result.
I also tried "python.exe > data.txt" and was amazed to find out that it won't redirect the output to the file.
So, may someone please shed some light over this?
Avi.
Well, your first misunderstanding appears to be the omission of the standard error file. Interactive messages and prompts are written to stderr, output to stdout:
C:\Steve>python.exe > python.txt Python 2.4 (#60, Nov 30 2004, 11:49:19) [MSC v.1310 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> 123 >>> 345 >>> ^Z
C:\Steve>type python.txt 123 345
When you try to write a program that communicates with a client that's intended for interactive use (such as the Python interpreter when called with no arguments), you have the problem of divining exactly when the client is waiting for input.
Rather than blame the Python interpreter, first write a program that interacts with (say) the Windows command-line interpreter.
If your experience is substantially different then it *might* be a problem with the interpreter. If your experience is more or less the same then the problem is probably to do with the nature of the interactions, which are bad enough when only considering stdin and stdout. When you add the stderr stream into the picture it's sometimes impossible to know when the interactive client is waiting for input.
One final comment: you haven't so far said *why* you want to interact with Python in this way. Given the availability of exec and eval(), just what is it that you are trying to do that they won't let you?
regards Steve -- Steve Holden http://www.holdenweb.com/ Python Web Programming http://pydish.holdenweb.com/ Holden Web LLC +1 703 861 4237 +1 800 494 3119 -- http://mail.python.org/mailman/listinfo/python-list
