PS> I'm not sure weather I should post this in a C++ echo or 
PS> OS/2 programming echo,
PS>  but here it goes:

This really goes in the OS/2 programming echo.

PS> Is there any way to multithread a C++ Class member-function? I'm using 
PS> VisualAge C++ 3.0, and I am trying to execute a member-function in a separate 
PS> thread. But the compiler says "error EDC3167: The
"_Optlink" qualifier cannot 

There are two ways around this.  One, which you probably already
considered is to instantiate the class in a utility (non-member)
function and call the member function from that utility.  E.g.

void utilityFoo ( void * )
{
  MyClass  myclass ;

  myclass.foo () ;

}

And then use utility method utilityFoo as the parameter for 
_beginthread.  This is also kind of a pain in the ass because you have
 to demangle the name the compiler gives 'void utilityFoo ( void * )'

The other way to do this is to use the OCL IThread class. (The
following is taken from the VAC++ 3.0 Frequently Asked Questions info 
file (CPPFAQ.INF, found in IBMCPP\HELP, the topic heading is "How do I 
start a Thread?")

   // MyClass has member function void foo()
   IThread thread;
   thread.start( new IThreadMemberFn( *this, foo ) )
 

2. If the code you want to run does not match the above descriptions,
you must write a "wrapper" using one of the following two techniques:

a. Derive from IThreadFn and implement run to call the desired member
   function of your object.  This may be difficult because you typically
   need to know what additional arguments to pass, and this technique
   provides no way to address that requirement.  However, it can be more
   syntactically elegant:  aThread.start(this) instead of aThread.start(
   new IThreadMemberFn(*this, T::foobar) ). Also, the lifetime of
   this must transcend the lifetime of the thread.

b. Derive a new class from IThreadFn.  Add data members for arguments
to
   the function you want to run, including the object that a member
   function might be invoked on.  Add a constructor that accepts
   references to the arguments as its arguments.  Finally, implement run
   to dispatch the function you want with the provided arguments.  The
   MLE sample program shipped with VisualAge C++ provides an example of
   this technique.  You could alternatively implement the function you
   want to run within MyThreadFn::run.

   The IThreadFn object is reference-counted so that it can be
   automatically deleted when the thread terminates.  As a result, if
   you use IThreadFn or a derived class, you must allocate the IThreadFn
   using the new operator and you must not delete it.
  

   I know this is a little complex, spend some time looking at the 
example code, the CPPFAQ.INF and the IThread and IThreadFn classes in 
the OCL reference.  If you are still stuck let us know!

Thanks

Peter

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