Re: A question about Objective C running without any Frameworks

[David Chisnall]

On 28 Aug 2009, at 23:38, Michael Durket wrote:

> Does anyone here know if an Objective C program, written to only  
> link with libobjc and no other Objective C
> frameworks (so that the programs can only use whatever objects  
> reside in libobjc like Object I presume)
> will operate correctly in a multi-threaded environment? Put another  
> way, can Objective C using only libobjc
> work everywhere C can - i.e. as an Apache module, or a device driver  
> (assuming proper interface code),
> or as system code?

Yes, libobjc is reentrant.  Very few bits of libobjc need to be thread  
safe in general use (message lookup does, for example, but that's a  
simple sparse array lookup).  The rest is protected by mutexes.  As  
long as you don't use any low-level runtime functions without reading  
the documentation about which mutex you need to acquire, it will all  
work.

David