The Auxiliary Library

Pushes onto the stack the field e from the metatable of the object at index obj and returns the type of the pushed value. If the object does not have a metatable, or if the metatable does not have this field, pushes nothing and returns LUA_TNIL.

Pushes onto the stack the metatable associated with name tname in the registry (see luaL_newmetatable) (nil if there is no metatable associated with that name). Returns the type of the pushed value.

Loads a buffer as a Lua chunk. This function uses lua_load to load the chunk in the buffer pointed to by buff with size sz.

This function returns the same results as lua_load. name is the chunk name, used for debug information and error messages.

Equivalent to luaL_loadfilex with mode equal to NULL.

Loads a file as a Lua chunk. This function uses lua_load to load the chunk in the file named filename. If filename is NULL, then it loads from the standard input. The first line in the file is ignored if it starts with a #.

The string mode works as in function lua_load.

This function returns the same results as lua_load, but it has an extra error code LUA_ERRFILE for file-related errors (e.g., it cannot open or read the file).

As lua_load, this function only loads the chunk; it does not run it.

Opens all standard Lua libraries into the given state.

https://www.lua.org/manual/5.3/manual.html#luaL_openlibs

If the registry already has the key tname, returns 0. Otherwise, creates a new table to be used as a metatable for userdata, adds to this new table the pair __name = tname, adds to the registry the pair [tname] = new table, and returns 1. (The entry __name is used by some error-reporting functions.)

In both cases pushes onto the stack the final value associated with tname in the registry.

Creates and returns a reference, in the table at index t, for the object at the top of the stack (and pops the object).

A reference is a unique integer key. As long as you do not manually add integer keys into table t, luaL_ref ensures the uniqueness of the key it returns. You can retrieve an object referred by reference r by calling lua_rawgeti l t r. Function luaL_unref frees a reference and its associated object.

If the object at the top of the stack is nil, luaL_ref returns the constant LUA_REFNIL. The constant LUA_NOREF is guaranteed to be different from any reference returned by luaL_ref.

Checks whether the function argument arg is a userdata of the type tname (see luaL_newmetatable) and returns the userdata address (see lua_touserdata). Returns NULL if the test fails.

https://www.lua.org/manual/5.3/manual.html#luaL_testudata

Creates and pushes a traceback of the stack l1. If msg is not NULL it is appended at the beginning of the traceback. The level parameter tells at which level to start the traceback.

Releases reference ref from the table at index t (see luaL_ref). The entry is removed from the table, so that the referred object can be collected. The reference ref is also freed to be used again.

Pushes onto the stack a string identifying the current position of the control at level lvl in the call stack. Typically this string has the following format:

chunkname:currentline:

Level 0 is the running function, level 1 is the function that called the running function, etc.

This function is used to build a prefix for error messages.

Key, in the registry, for table of loaded modules.

Key, in the registry, for table of preloaded loaders.

Reference to a stored value.

Convert a reference to its C representation.

Create a reference from its C representation.