Re: Limiting to one instance

Jon wrote:
> Using FindWindow() introduces a possible race condition

I stand corrected. I was using this for installers, not for actually
preventing double-startup of the same app. So scratch my remark on
FindWindow being useful here.

Stefan wrote:
> But CreateMutex etc *is* intended for the purpose.

Well, I was replying to Andrew's comment on IP ports not being
suitable for that purpose. In that context, I believe CreateMutex is
not any more suitable. CreateMutex (named) is intended for the purpose
of synchronizing two processes by actually using a mutex. Using the
mutex's mere existance to note anything is as much of a hack as using
an IP port for that. The fact that there are personal firewalls in the
modern world is another hack as well. IP port creation was not
supposed to be intercepted in this way - in the original design,
AFAIK.

Simply trying to point out the fact that we frequently have to use
something for what it is not supposed to be used for. And often one
can't predict all possible side-effects. Like that poor guy didn't
predict that a firewall would make the IP-port solution useless, like
FindWindow is not perfect due to a possible race condition, like the
CreateMutex might have possible user-switching problem (although not
likely, as local creation is default, IIRC).

Put simply: unless the manual says "this can be used to do XYZ", then
if you are using it for that, you are risking possible problems.
(Although, you are probably risking possible problems even if it does
say so. :p )

JM2C,
Alen


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