Bidirectional communication through pipes: read/write popen()

[Fredrik Lundh]

Oleg Broytmann <phd at sun.med.ru> wrote:
> On 17 Oct 1999, Hrvoje Niksic wrote:
> > def rwpopen(input, command, args=[]):
>                               ^^^^^^^
>    There was well-know problem with passing mutable object as a default.
> Not sure if it was fixed in recent versions of Python...

well, that's only a problem if you modify the object
inside the function...

(and no, it hasn't been fixed.  I doubt it can be
fixed without breaking stuff).

...

but to make the code a bit more flexible, I'd change
the execvp call to:

os.execvp(command, (command,) + tuple(args))

or, if you prefer:

os.execvp(command, [command] + list(args))

(this allows the caller to use *any* kind of sequence,
not just a list).

</F>

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