int lua_next (lua_State *L, int index);

Pops a key from the stack, and pushes a key-value pair from the table at the given index (the "next" pair after the given key). If there are no more elements in the table, then  returns 0 (and pushes nothing).

A typical traversal looks like this:

/* table is in the stack at index 't' */     lua_pushnil(L);  /* first key */     while (lua_next(L, t) != 0) {       /* uses 'key' (at index -2) and 'value' (at index -1) */       printf("%s - %s\n",              lua_typename(L, lua_type(L, -2)),              lua_typename(L, lua_type(L, -1)));       /* removes 'value'; keeps 'key' for next iteration */       lua_pop(L, 1);     }

While traversing a table, do not call  directly on a key, unless you know that the key is actually a string. Recall that  changes the value at the given index; this confuses the next call to .