[C++-sig] How to capture stdout/stderr?

[Bert Peers]

At 01:08 28/08/2004 -0400, you wrote:
>Hi,
>
>I am trying to capture stdout and stderr from Python using boost.python.

Here is my, considerably low-tech, code :

At init time,

-----------
const std::string CatchOutput =
         "class StdoutCatcher:\n"
         "\tdef __init__(self):\n"
         "\t\tself.data = ''\n"
         "\tdef write(self, stuff):\n"
         "\t\tself.data = self.data + stuff\n"
         "\n"
         "import sys\n"
         "TheStdoutCatcher = StdoutCatcher()\n"
         "sys.stdout = TheStdoutCatcher\n";

Run (CatchOutput);      // thin wrapper to run a snippet
-----------

and then after some python code has run :

-----------
using namespace boost::python;
object Catcher (main_namespace ["TheStdoutCatcher"]);
object CatcherData (borrowed (PyObject_GetAttrString (Catcher.ptr (), 
"data")));

const std::string &S = extract<std::string>(CatcherData);
Output += S;    // some log string
Run ("sys.stdout.data=''\n");
-----------

Note I'm pretty new at this, so the only warranty is
"the above didn't crash so far" :)  Now that I paste
it, I'm not sure about that const ref to the result of
extract.


hth,
bert