Many thanks Dodi.
Antonio.
Le 23/03/2012 10:59, Hans-Peter Diettrich a écrit :
Antonio Fortuny schrieb:
Trying to be as much clear as possible, there are some sentences:
Assuming this few statements (aka my own rules when writing thread's
code):
a. all thread code+data are encapsulated into a TThread object
b. "Thread safe" means that there is no overlap of data references
from thread to thread, the main thread inclusive, and that no
references are passed outside the thread's control from thread to
thread (by the means of the owner or global vars for instance)
c. the thread creator does not interfere in any way with the thread's
data and methods as soon as the thread has been started (Terminated
execpted of course)
d. no function neither procedure calls are made to any function or
procedure defined outside of the thread control (aka self defined
methods)
Looks good :-)
Do you all agree on the following asserts:
1. All variables in the thread definition (TThread's private,
protected and public variables) are "Thread safe" BUT are accessible
to the thread creator
The OPL visibility rules apply. Public members are accessible by
everybody, others only from inside the unit where the thread class is
declared. As long as the thread creator doesn't export the thread
object, nobody else can access it, of course.
I agree with you that the assertion could be more precise when talking
about object members visibility. But we are talking abount OOP, aren't
we ? 8-)
5. all useful code a thread needs should be encapsultated into a
TObject descendant and instantiated within the thread's space.
This can all be implemented in the derived TThread class.
So, building an object around this utility code does not enlarge thread
safety ?
6. all methods defined in the thread's definition, aprat from the
EXECUTE procedure (obvious !), run into the thread creator space
(the one which instantiates the thread, aka does something like
wThread := TMyThread.Create (False) )
Every procedure or method runs in the context of its *caller*.
Everything called from the thread's Execute method executes in the
thread context (stack, threadvars).
Sounds very clear. Big idea using few words. I appeciate.
DoDi
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