Lua学习笔记之function type

Here we list all functions and types from the C API in alphabetical order. Each function has an indicator like this:[-o, +p, x]

The first field, 

o

, is how many elements the function pops from the stack. 

The second field, 

p

, is how many elements the function pushes onto the stack. (Any function always pushes its results after popping its arguments.) 

A field in the form 

x|y

 means the function can push (or pop) 

x

 or 

y

 elements, depending on the situation; an interrogation mark '

?

'
means that we cannot know how many elements the function pops/pushes by looking only at its arguments (e.g., they may depend on what is on the stack). 

The third field, 

x

, tells whether the function may throw errors: '

-

' means the function never throws any error; '

m

' means the function may throw an error
only due to not enough memory; '

e

' means the function may throw other kinds of errors; '

v

' means the function may throw an error on purpose.