Re: Correct way to push an empty string?

[Tim Hill <drtimhill@...>]

On Aug 23, 2015, at 4:36 PM, Igor Ehrlich <iehrlich@iponweb.net> wrote:

> C99 specifies that it is fine to pass zero to memcpy as the size parameter.

7.24.1(2): Where an argument declared as size_t n specifies the length of the array for a

function, n can have the value zero on a call to that function. Unless explicitly stated

otherwise in the description of a particular function in this subclause, pointer arguments

on such a call shall still have valid values, as described in 7.1.4. On such a call, a

function that locates a character finds no occurrence, a function that compares two

character sequences returns zero, and a function that copies characters copies zero

characters.

My question wasn't about passing zero as the size/length, it was about acceptable values for the associated memory pointers when the size was zero. On two different occasions I’ve had C runtimes that have faulted when passed a NULL pointer to (say) memcpy when the length was zero. I agree that this is not in accordance with standards, nor is it particularly sensible, but I wanted clarity on how Lua handled such a situation (since the specs are silent on this).

—Tim