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- Subject: Re: Print address of string in Lua
- From: Matthew Wild <mwild1@...>
- Date: Thu, 15 Dec 2011 15:39:40 +0000
On 15 December 2011 13:52, rahul sharma <email@example.com> wrote:
> Hi All,
> Thanks for your kind reply. Why I want the address in Lua is because I want
> to know the address in Lua, then I will pass that string to C, and in C, I
> will get the address of that string using lua_tostring(). So if these two
> match, then I can be sure that no copying is done in lua on passing string
> from Lua to C.
Lua does not perform any copying when passing a string from Lua -> C.
It is up to you to copy the string if you need to (since Lua may move
or delete it when it no longer needs it).
If all you want to do is pass a pointer to a string *through* Lua so
that Lua doesn't copy it from C, you can push the pointer as a
userdata or lightuserdata. More information on these can be found at:
In this case it's up to you to make sure the string remains accessible
in C while Lua still has a reference to it.