python sys.stdout and C++ iostreams::cout

Chris Angelico rosuav at
Thu Jan 17 16:42:24 CET 2013

On Fri, Jan 18, 2013 at 2:02 AM, Utpal Sarkar <doetoe at> wrote:
> I was assuming that sys.stdout would be referencing the same physical stream as iostreams::cout running in the same process, but this doesn't seem to be the case.

That's more-or-less true, but there will likely be separate buffering,
so even without redirection you might see some oddities. But the
problem with your code is that you're not actually redirecting stdout
in any way; you're catching, at a fairly high level, everything that
Python would otherwise have sent there.

Is there any way that you can get the C++ code to offer a way to
redirect its output? Otherwise, you're going to have to fiddle around
with the usual mess of I/O redirection (with dup2), and you can only
send it to what the OS sees as a file (so, no StringIO buffer). So to
achieve your goal, you may need either a temporary physical file, or
some sort of pipe (and worry about reading from it before it fills up,
etc, etc). There may be alternatives, but in any case, the easiest way
is going to be with some assistance from the C++ function.


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