<[EMAIL PROTECTED]> wrote: 8<------------------ > The C programm gets its "commands" from its stdin and sends its state > to stdout. Thus I have some kind of dialog over stdin. > > So, once I start the C Program from the shell, I immediately get its > output in my terminal. If I start it from a subprocess in python and > use python's sys.stdin/sys.stdout as the subprocess' stdout/stdin I > also get it immediately.
so why don't you just write to your stdout and read from your stdin? > > BUT If I use PIPE for both (so I can .write() on the stdin and .read() This confuses me - I assume you mean write to the c program's stdin? > from the subprocess' stdout stream (better: file descriptor)) reading > from the subprocess stdout blocks forever. If I write something onto > the subprocess' stdin that causes it to somehow proceed, I can read > from its stdout. This sounds like the c program is getting stuck waiting for input... > > Thus a useful dialogue is not possible. > If you are both waiting for input, you have a Mexican standoff... And if you are using threads, and you have issued a .read() on a file, then a .write() to the same file, even followed by a .flush() will not complete until after the completion of the .read(). So in such a case you have to unblock the file, and do the .read() in a try - except clause, to "free up" the "file driver" so that the .write() can complete. But I am not sure if this is in fact your problem, or if it is just normal synchronisation hassles... - Hendrik -- http://mail.python.org/mailman/listinfo/python-list
