C API functions and types: getallocf–getiuservalue

lua_getallocf

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lua_Alloc lua_getallocf (lua_State *L, void **ud);

Returns the memory-allocator function of a given state. If ud is not NULL, Lua stores in *ud the opaque pointer given when the memory-allocator function was set.

lua_getfield

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int lua_getfield (lua_State *L, int index, const char *k);

Pushes onto the stack the value t[k], where t is the value at the given index. As in Lua, this function may trigger a metamethod for the “index” event (see §2.4).

Returns the type of the pushed value.

lua_getextraspace

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void *lua_getextraspace (lua_State *L);

Returns a pointer to a raw memory area associated with the given Lua state. The application can use this area for any purpose; Lua does not use it for anything.

Each new thread has this area initialized with a copy of the area of the main thread.

By default, this area has the size of a pointer to void, but you can recompile Lua with a different size for this area. (See LUA_EXTRASPACE in luaconf.h.)

lua_getglobal

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int lua_getglobal (lua_State *L, const char *name);

Pushes onto the stack the value of the global name. Returns the type of that value.

lua_geti

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int lua_geti (lua_State *L, int index, lua_Integer i);

Pushes onto the stack the value t[i], where t is the value at the given index. As in Lua, this function may trigger a metamethod for the “index” event (see §2.4).

Returns the type of the pushed value.

lua_getmetatable

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int lua_getmetatable (lua_State *L, int index);

If the value at the given index has a metatable, the function pushes that metatable onto the stack and returns 1. Otherwise, the function returns 0 and pushes nothing on the stack.

lua_gettable

[-1, +1, e]

int lua_gettable (lua_State *L, int index);

Pushes onto the stack the value t[k], where t is the value at the given index and k is the value on the top of the stack.

This function pops the key from the stack, pushing the resulting value in its place. As in Lua, this function may trigger a metamethod for the “index” event (see §2.4).

Returns the type of the pushed value.

lua_gettop

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int lua_gettop (lua_State *L);

Returns the index of the top element in the stack. Because indices start at 1, this result is equal to the number of elements in the stack; in particular, 0 means an empty stack.

lua_getiuservalue

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int lua_getiuservalue (lua_State *L, int index, int n);

Pushes onto the stack the n-th user value associated with the full userdata at the given index and returns the type of the pushed value.

If the userdata does not have that value, pushes nil and returns LUA_TNONE.