is the number of arguments that you pushed onto the stack. All arguments and the function value are popped from the stack, and the function results are pushed. The number of results are adjusted to , unless is . In that case, all results from the function are pushed. Lua takes care that the returned values fit into the stack space. The function results are pushed onto the stack in direct order (the first result is pushed first), so that after the call the last result is on the top.

Here it is in C:

(We did this example using only the raw functions provided by Lua’s API, to show all the details. Usually programmers define and use several macros and auxiliary functions that provide higher level access to Lua. See the source code of the standard libraries for examples.)