lua_tostring[-0, +0, m] const char *lua_tostring (lua_State *L, int index); Equivalent to lua_tolstring with len equal to NULL.

lua_tothread[-0, +0, –] lua_State *lua_tothread (lua_State *L, int index); Converts the value at the given index to a Lua thread (represented as lua_State*). This value must be a thread; otherwise, the function returns NULL.

lua_touserdata[-0, +0, –] void *lua_touserdata (lua_State *L, int index); If the value at the given index is a full userdata, returns its block address. If the value is a light userdata, returns its pointer. Otherwise, returns NULL.

lua_type[-0, +0, –] int lua_type (lua_State *L, int index); Returns the type of the value in the given valid index, or LUA_TNONE for a non-valid (but acceptable) index. The types returned by lua_type are coded by the following constants defined in lua.h: LUA_TNIL (0), LUA_TNUMBER, LUA_TBOOLEAN, LUA_TSTRING, LUA_TTABLE, LUA_TFUNCTION, LUA_TUSERDATA, LUA_TTHREAD, and LUA_TLIGHTUSERDATA.

lua_typename[-0, +0, –] const char *lua_typename (lua_State *L, int tp); Returns the name of the type encoded by the value tp, which must be one the values returned by lua_type.

lua_Unsigned typedef ... lua_Unsigned; The unsigned version of lua_Integer.

lua_upvalueid[-0, +0, –] void *lua_upvalueid (lua_State *L, int funcindex, int n); Returns a unique identifier for the upvalue numbered n from the closure at index funcindex. These unique identifiers allow a program to check whether different closures share upvalues. Lua closures that share an upvalue (that is, that access a same external local variable) will return identical ids for those upvalue indices. Parameters funcindex and n are as in function lua_getupvalue, but n cannot be grea

lua_upvalueindex[-0, +0, –] int lua_upvalueindex (int i); Returns the pseudo-index that represents the i-th upvalue of the running function (see §4.4).

lua_upvaluejoin[-0, +0, –] void lua_upvaluejoin (lua_State *L, int funcindex1, int n1, int funcindex2, int n2); Make the n1-th upvalue of the Lua closure at index funcindex1 refer to the n2-th upvalue of the Lua closure at index funcindex2.

lua_version[-0, +0, –] const lua_Number *lua_version (lua_State *L); Returns the address of the version number (a C static variable) stored in the Lua core. When called with a valid lua_State, returns the address of the version used to create that state. When called with NULL, returns the address of the version running the call.