lua_isthread[-0, +0, –] int lua_isthread (lua_State *L, int index); Returns 1 if the value at the given index is a thread, and 0 otherwise.

lua_istable[-0, +0, –] int lua_istable (lua_State *L, int index); Returns 1 if the value at the given index is a table, and 0 otherwise.

lua_isstring[-0, +0, –] int lua_isstring (lua_State *L, int index); Returns 1 if the value at the given index is a string or a number (which is always convertible to a string), and 0 otherwise.

lua_isnumber[-0, +0, –] int lua_isnumber (lua_State *L, int index); Returns 1 if the value at the given index is a number or a string convertible to a number, and 0 otherwise.

lua_isnoneornil[-0, +0, –] int lua_isnoneornil (lua_State *L, int index); Returns 1 if the given index is not valid or if the value at this index is nil, and 0 otherwise.

lua_isnone[-0, +0, –] int lua_isnone (lua_State *L, int index); Returns 1 if the given index is not valid, and 0 otherwise.

lua_isnil[-0, +0, –] int lua_isnil (lua_State *L, int index); Returns 1 if the value at the given index is nil, and 0 otherwise.

lua_islightuserdata[-0, +0, –] int lua_islightuserdata (lua_State *L, int index); Returns 1 if the value at the given index is a light userdata, and 0 otherwise.

lua_isinteger[-0, +0, –] int lua_isinteger (lua_State *L, int index); Returns 1 if the value at the given index is an integer (that is, the value is a number and is represented as an integer), and 0 otherwise.

lua_isfunction[-0, +0, –] int lua_isfunction (lua_State *L, int index); Returns 1 if the value at the given index is a function (either C or Lua), and 0 otherwise.