Re: doubts in multi threaded application (win32 console + mfc)
"John" wrote
Hi All,
I have some basic doubts in technical wise.
Environment: windows 2003 server, VC++ 6.0 (win
32 console + MFC
SUPPORT)
I am developing multi threaded application
(server). In each
thread, I am creating objects in stack memory. Each object
takes 2500 bytes.
Is it correct way to creating objects in stack memory for
multi threaded
application?
Which way to choose when creating objects (on stack or from
heap) depends on how you intend to use them. If you're
planning to share these objects between threads, then
creating them on stack can be dangerous, since lifetime of
threads can differ, therefore one thread may attempt to
access nonexisting object.
However, if objects are intended for regular local use, then
creating them on stack is preferable way.
In which memory (Stack or Heap) I have to create objects
to improve the
performance?
Again, it depends on the nature of an object and usage
pattern. Generally speaking, creating objects on stack is
faster than allocation from heap. However, there are
counterexamples, as well. Carl Daniel already explained that
CString won't gain much being allocated on stack since it
allocates memory from heap for internal buffer. The same is
true for many standard containers, too (like std::vector,
std::map, etc.).
I am using so many CString objects in this application.
Will it give any
unexpected results in my application in any conditions
like application
crash or performance hit?
If you share CString objects between threads, then you must
guard an access to them, so only one thread at a time can
access CString object. If two or more threads will attempt
to change an object simultaneously, then it will likely lead
to crash or data corruption. CString class doesn't implement
any synchronization mechanism internally.
Try-Catch blocks will hit performance for multi threaded
application. Is it
correct?
No, it's not correct. Try-Catch blocks have negligible
effect on performance.
HTH
Alex