On 03/04/2010 11:59 AM, Neal Becker wrote:
int main () {
Py_Initialize();
object main_module = import("__main__");
object main_namespace = main_module.attr("__dict__");
try {
object result = exec ("import sys\n"
"sys.path.append('./')\n"
"import test_embed\n"
"test_embed.five_square()\n",
main_namespace);
int five_squared = extract<int> (result);
std::cout<< five_squared<< '\n';
}
catch (error_already_set const&) {
PyErr_Print();
}
}
test_embed.py:
--------------------
def five_square ():
return 5 ** 2
I get:
./test_embed
TypeError: No registered converter was able to produce a C++ rvalue of type
int from this Python object of type NoneType
Why did exec return None? I expected it to return the result of
"test_embed.five_squared()", which is the int 25. What is the meaning of
the return of exec_file? A python module can't return a result.
This is a straight wrapping of Python's C API. AFAICT, the return value
is only useful to determine whether the call was successful. Thus, None
may indicate an internal error, which you can check for with
PyErr_Occured(). (I'm actually surprised we don't catch this internally
and then raise an err_already_set exception !)
The real error could be that the interpreter wasn't able to import one
of the modules (wrong PYTHONPATH ?), or something similar.
Regards,
Stefan
--
...ich hab' noch einen Koffer in Berlin...
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