pybind11/tests/test_constants_and_functions.cpp
Jason Rhinelander 6e036e78a7 Support binding noexcept function/methods in C++17
When compiling in C++17 mode the noexcept specifier is part of the
function type.  This causes a failure in pybind11 because, by omitting
a noexcept specifier when deducing function return and argument types,
we are implicitly making `noexcept(false)` part of the type.

This means that functions with `noexcept` fail to match the function
templates in cpp_function (and other places), and we get compilation
failure (we end up trying to fit it into the lambda function version,
which fails since a function pointer has no `operator()`).

We can, however, deduce the true/false `B` in noexcept(B), so we don't
need to add a whole other set of overloads, but need to deduce the extra
argument when under C++17.  That will *not* work under pre-C++17,
however.

This commit adds two macros to fix the problem: under C++17 (with the
appropriate feature macro set) they provide an extra `bool NoExceptions`
template argument and provide the `noexcept(NoExceptions)` deduced
specifier.  Under pre-C++17 they expand to nothing.

This is needed to compile pybind11 with gcc7 under -std=c++17.
2016-12-14 20:40:49 +01:00

105 lines
3.3 KiB
C++

/*
tests/test_constants_and_functions.cpp -- global constants and functions, enumerations, raw byte strings
Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
All rights reserved. Use of this source code is governed by a
BSD-style license that can be found in the LICENSE file.
*/
#include "pybind11_tests.h"
enum MyEnum { EFirstEntry = 1, ESecondEntry };
std::string test_function1() {
return "test_function()";
}
std::string test_function2(MyEnum k) {
return "test_function(enum=" + std::to_string(k) + ")";
}
std::string test_function3(int i) {
return "test_function(" + std::to_string(i) + ")";
}
py::str test_function4(int, float) { return "test_function(int, float)"; }
py::str test_function4(float, int) { return "test_function(float, int)"; }
py::bytes return_bytes() {
const char *data = "\x01\x00\x02\x00";
return std::string(data, 4);
}
std::string print_bytes(py::bytes bytes) {
std::string ret = "bytes[";
const auto value = static_cast<std::string>(bytes);
for (size_t i = 0; i < value.length(); ++i) {
ret += std::to_string(static_cast<int>(value[i])) + " ";
}
ret.back() = ']';
return ret;
}
// Test that we properly handle C++17 exception specifiers (which are part of the function signature
// in C++17). These should all still work before C++17, but don't affect the function signature.
namespace test_exc_sp {
int f1(int x) noexcept { return x+1; }
int f2(int x) noexcept(true) { return x+2; }
int f3(int x) noexcept(false) { return x+3; }
int f4(int x) throw() { return x+4; } // Deprecated equivalent to noexcept(true)
struct C {
int m1(int x) noexcept { return x-1; }
int m2(int x) const noexcept { return x-2; }
int m3(int x) noexcept(true) { return x-3; }
int m4(int x) const noexcept(true) { return x-4; }
int m5(int x) noexcept(false) { return x-5; }
int m6(int x) const noexcept(false) { return x-6; }
int m7(int x) throw() { return x-7; }
int m8(int x) const throw() { return x-8; }
};
}
test_initializer constants_and_functions([](py::module &m) {
m.attr("some_constant") = py::int_(14);
m.def("test_function", &test_function1);
m.def("test_function", &test_function2);
m.def("test_function", &test_function3);
#if defined(PYBIND11_OVERLOAD_CAST)
m.def("test_function", py::overload_cast<int, float>(&test_function4));
m.def("test_function", py::overload_cast<float, int>(&test_function4));
#else
m.def("test_function", static_cast<py::str (*)(int, float)>(&test_function4));
m.def("test_function", static_cast<py::str (*)(float, int)>(&test_function4));
#endif
py::enum_<MyEnum>(m, "MyEnum")
.value("EFirstEntry", EFirstEntry)
.value("ESecondEntry", ESecondEntry)
.export_values();
m.def("return_bytes", &return_bytes);
m.def("print_bytes", &print_bytes);
using namespace test_exc_sp;
py::module m2 = m.def_submodule("exc_sp");
py::class_<C>(m2, "C")
.def(py::init<>())
.def("m1", &C::m1)
.def("m2", &C::m2)
.def("m3", &C::m3)
.def("m4", &C::m4)
.def("m5", &C::m5)
.def("m6", &C::m6)
.def("m7", &C::m7)
.def("m8", &C::m8)
;
m2.def("f1", f1);
m2.def("f2", f2);
m2.def("f3", f3);
m2.def("f4", f4);
});