routine to mark a function / variable as requiring safety
template <typename T>
auto protect( T&& value );sol::protect( my_func ) allows you to protect a function call or member variable call when it is being set to Lua. It can be used with usertypes or when just setting a function into sol. Below is an example that demonstrates that a call that would normally not error without :doc:`Safety features turned on<../safety>` that instead errors and makes the Lua safety-call wrapper pcall fail:
.. literalinclude:: ../../../examples/source/protect.cpp
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