lua_newuserdata
[-0, +1, m]
void *lua_newuserdata (lua_State *L, size_t size);

This function allocates a new block of memory with the given size, pushes onto the stack a new full userdata with the block address, and returns this address.

Userdata represent C values in Lua. A full userdata represents a block of memory. It is an object (like a table): you must create it, it can have its own metatable, and you can detect when it is being collected. A full userdata is only equal to itself (under raw equality).

When Lua collects a full userdata with a gc metamethod, Lua calls the metamethod and marks the userdata as finalized. When this userdata is collected again then Lua frees its corresponding memory.

EVERYTHING
Functions and Types
lua_Alloc
lua_atpanic
lua_call
lua_CFunction
lua_checkstack
lua_close
lua_concat
lua_cpcall
lua_createtable
lua_dump
lua_equal
lua_error
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lua_newuserdata
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lua_xmove
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