>Does it overcome the problem that you reported earlier, that the contents of the output file from BCP were out of order?
Yes, it does. But, to be honest, I don't know how!!! "John Machin" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > On 10/06/2006 3:00 AM, A.M wrote: >> Here is what I came up with after John and Fredrik's help. >> >> import os >> import sys >> def Execute(shell_command,logStream = sys.stdout): >> print >>logStream, shell_command >> child_stdin, child_stdout_and_stderr = os.popen4(shell_command) >> commad_output = child_stdout_and_stderr.read() >> print >>logStream, commad_output >> return_code = child_stdout_and_stderr.close() >> return_code = return_code or child_stdin.close() >> print >>logStream, "Return Code: " , return_code >> >> Execute ("DIR") >> >> Execute ("MD :") >> >> I tested it and so far it behaves the way that I want. >> > > Does it overcome the problem that you reported earlier, that the contents > of the output file from BCP were out of order? If not, you may like to try > popen3(). It's quite possible (and indeed desirable) that the child's > stderr is not buffered (so that error messages appear immediately) but the > child's stdout is buffered (for efficiency), and when the buffer is > flushed governs the order of appearance in a single output stream. >> >> >> The tricky part is that when you use popen4, you have to close both >> returned streams to be able to get the return code. I wasn't able to find >> that in the documentation. > > In general it is good practice to hand back resources (e.g. close files) > explicitly as soon as you are finished with them. This is especially > important for files open for writing, in case there are problems like out > of disk space, device not functioning etc. Also when you are dealing with > a child process it makes some sense to close its stdin first just in case > it is waiting for that, and will then write something to stdout, which may > fail, causing it to write to stderr. So I guess that the documenter didn't > stumble onto the "tricky part" :-) > > The "tricky part" for popen and friends seems to be that the return code > is handed back upon close of the *last* file: > > |>>> h = os.popen3('md : ') > |>>> [h[x].close() for x in 2, 1, 0] > [None, None, 1] > > Looks like you get to report a documentation "problem" after all :-) > > Cheers, > John > > -- http://mail.python.org/mailman/listinfo/python-list
