h2-mod/deps/sol2/examples/source/tutorials/pointer_lifetime.cpp
2024-03-07 03:33:59 -05:00

83 lines
1.6 KiB
C++

#define SOL_ALL_SAFETIES_ON 1
#include <sol/sol.hpp>
struct my_type {
void stuff() {
}
};
int main() {
sol::state lua;
/*
// AAAHHH BAD
// dangling pointer!
lua["my_func"] = []() -> my_type* { return new my_type(); };
// AAAHHH!
lua.set("something", new my_type());
// AAAAAAHHH!!!
lua["something_else"] = new my_type();
*/
// :ok:
lua["my_func0"] = []() -> std::unique_ptr<my_type> {
return std::make_unique<my_type>();
};
// :ok:
lua["my_func1"] = []() -> std::shared_ptr<my_type> {
return std::make_shared<my_type>();
};
// :ok:
lua["my_func2"] = []() -> my_type { return my_type(); };
// :ok:
lua.set(
"something", std::unique_ptr<my_type>(new my_type()));
std::shared_ptr<my_type> my_shared
= std::make_shared<my_type>();
// :ok:
lua.set("something_else", my_shared);
// :ok:
auto my_unique = std::make_unique<my_type>();
lua["other_thing"] = std::move(my_unique);
// :ok:
lua["my_func5"] = []() -> my_type* {
static my_type mt;
return &mt;
};
// THIS IS STILL BAD DON'T DO IT AAAHHH BAD
// return a unique_ptr that's empty instead
// or be explicit!
lua["my_func6"] = []() -> my_type* { return nullptr; };
// :ok:
lua["my_func7"]
= []() -> std::nullptr_t { return nullptr; };
// :ok:
lua["my_func8"] = []() -> std::unique_ptr<my_type> {
// default-constructs as a nullptr,
// gets pushed as nil to Lua
return std::unique_ptr<my_type>();
// same happens for std::shared_ptr
};
// Acceptable, it will set 'something' to nil
// (and delete it on next GC if there's no more references)
lua.set("something", nullptr);
// Also fine
lua["something_else"] = nullptr;
return 0;
}