[ceph.git] / ceph / src / boost / libs / python / doc / reference / call.qbk

[section boost/python/call.hpp]
[section Introduction]
 <boost/python/call.hpp> defines the call family of overloaded function templates, used to invoke Python callable objects from C++. 
[endsect]
[section Function `call`]
``
template <class R, class A1, class A2, ... class An>
R call(PyObject* callable, A1 const&, A2 const&, ... An const&)
``
[variablelist
[[Requires][R is a pointer type, reference type, or a complete type with an accessible copy constructor]]
[[Effects][Invokes callable(a1, a2, ...an) in Python, where a1...an are the arguments to call(), converted to Python objects. ]]
[[Returns][The result of the Python call, converted to the C++ type R.]]
[[Rationale][For a complete semantic description and rationale, see this page. ]]
]
[endsect]
[section Example]
The following C++ function applies a Python callable object to its two arguments and returns the result. If a Python exception is raised or the result can't be converted to a double, an exception is thrown. 
``
double apply2(PyObject* func, double x, double y)
{
   return boost::python::call<double>(func, x, y);
}
``
[endsect]
[endsect]
Commit	Line	Data
7c673cae FG	1	[section boost/python/call.hpp]
	2	[section Introduction]
	3	<boost/python/call.hpp> defines the call family of overloaded function templates, used to invoke Python callable objects from C++.
	4	[endsect]
	5	[section Function `call`]
	6	``
	7	template <class R, class A1, class A2, ... class An>
	8	R call(PyObject* callable, A1 const&, A2 const&, ... An const&)
	9	``
	10	[variablelist
	11	[[Requires][R is a pointer type, reference type, or a complete type with an accessible copy constructor]]
	12	[[Effects][Invokes callable(a1, a2, ...an) in Python, where a1...an are the arguments to call(), converted to Python objects. ]]
	13	[[Returns][The result of the Python call, converted to the C++ type R.]]
	14	[[Rationale][For a complete semantic description and rationale, see this page. ]]
	15	]
	16	[endsect]
	17	[section Example]
	18	The following C++ function applies a Python callable object to its two arguments and returns the result. If a Python exception is raised or the result can't be converted to a double, an exception is thrown.
	19	``
	20	double apply2(PyObject* func, double x, double y)
	21	{
	22	return boost::python::call<double>(func, x, y);
	23	}
	24	``
	25	[endsect]
	26	[endsect]