Re: thread safety.

[Asko Kauppi <askok@...>]

The re-entrant gmtime_r() and localtime_r() are not ANSI C, I believe.  
You can provide a patch but inclusion of non-ANSI C features has  
seemed to be a 'no'. Maybe this will change, eventually.

"The asctime_r(), ctime_r(), gmtime_r(), and localtime_r() functions  
are expected to conform to ISO/IEC 9945-1:1996 (``POSIX.1'')"

Can you post a case where using such functions really presents a  
hazard, in a multithreaded application?

Why do you think 'system' is a problem?  Maybe it's been on the  
warning list because when you launch external programs, there's no  
guarantee how multithread unfriendly they could be? I find no problem  
with 'system()' itself.

-asko



George Neill kirjoitti 12.6.2009 kello 3:11:

> Hi All,
>
> Thanks for awesome Lua language, this is my first post to the  
> mailing list!
>
> I did a quick double check for some known non-reentrant functions and
> I found a handful of potential MT issues in loslib.c
>
> os_execute calls system() not MT safe.
> os_date calls either gmtime() or localtime() both are not MT safe.
>
> ... possibly others?
>
> I'd like to fix those which can be fixed and provide a patch, would it
> be preferable to enable a macro named something like
> LUA_USE_REENTRANT?
>
> TIA,
> George