-=> Quoting Craig Swanson to Phil Crown <=- 

 CS> Making code thread-safe usually involves the following:

 CS> 1) Avoid global variables

 CS> 2) Use local (i.e., auto or allocated on the stack) variables

Does this mean making sure that the compiler/optimizer doesn't register any
local variables?  Someone mentioned a bug in Borland that it was ignoring
the command not to register local variables or something like that.

 CS> 3) Protect resources that are not strictly local using mutex
 CS> semaphores or handle them using some other scheme such as atomic
 CS> bit test-and-set, inc/dec, and exchange operations

 CS> Making code SMP-safe takes it one step further as you must then
 CS> consider that some practices that would be safe on a single CPU system
 CS> will not be safe on a multiple CPU system.  For instance, a simple
 CS> Intel x86 INC instruction used to update a counter being handled by
 CS> multiple threads would need to have a LOCK prefix before it to make it
 CS> SMP-safe.

I know how to use mutex semaphores and I doubt anything I write will ever
run on an SMP system.

Thanks!

Phil
Fido:  1:124/8014.1 | Internet:  phil.crown{at}bluecafe.com


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