[Lazarus] Synchronize problem in linux

[Giuliano Colla]

Zaher Dirkey ha scritto:
>
>
> On Wed, May 25, 2011 at 2:33 PM, <michael.vancanneyt at wisa.be 
> <mailto:michael.vancanneyt at wisa.be>> wrote:
>
>
>
>     On Wed, 25 May 2011, Giuliano Colla wrote:
>
>         michael.vancanneyt at wisa.be <mailto:michael.vancanneyt at wisa.be>
>         ha scritto:
>
>
>
>             On Wed, 25 May 2011, Vincent Snijders wrote:
>
>                 2011/5/25  <michael.vancanneyt at wisa.be
>                 <mailto:michael.vancanneyt at wisa.be>>:
>
>                             No. You should use a
>                             TMultiReadExclusiveWriteSynchronizer object to
>                             synchronize access to your object, or use
>                             a critical section.
>
>
>                         Ehm, he made sure that only one thread
>                         accesses the TStringList at a
>                         time.
>
>
>                     To me, this is not obvious from his mail ?
>
>
>                 I thought it was obvious from:
>                 "The logic of the application itself made it sure that
>                 there was no
>                 conflict whatsoever. "
>
>                 But maybe that was not not what Giuliano meant by "no
>                 conflict".
>
>
>             This is what was not clear to me...
>
>             If no conflict can mean 'it adds only', then there is a
>             conflict at a lower
>             level, because adding can mean a reallocation of the array
>             of strings.
>
>         The full picture is:
>         1) The main thread creates the String List, and doesn't touch
>         it any more.
>         2) The other thread is activated and it is the only one which
>         appends strings to the list.
>         3) When the other thread is terminated, the main thread
>         processes the list.
>
>         I would expect that whatever activity occurs as an effect of
>         appending strings (such as reallocating the array) would occur
>         in the context of the thread performing the action, that all
>         pertinent information is stored in fields of the object
>         itself, and that the main thread is never involved.  Am I
>         wrong on this aspect?
>
>
>     No, you are right. If it is designed as described above, then it
>     should
>     work.
>
>     Michael.
>
>  
> But that mean he have only one thread worked at same time.
>
There's quite a number of other activities going on, which I didn't 
describe, because they were not relevant in this context. If what I 
described had been the only task to perform, then multithreading would 
be unnecessary.

Giuliano