Mac Forum / Programming / CodeWarrior / March 2004

If you're doing C++, Pro 9 introduces a nice thread-local-data smart
pointer:

#include <iostream>
#include <msl_thread>

Metrowerks::thread_specific_ptr<int> value;

void increment()
{
   ++*value;
}

Metrowerks::mutex cout_mutex;

void thread_proc()
{
   value.reset(new int(0));
   for (int i = 0; i < 1000; ++i)
       increment();
   Metrowerks::mutex::scoped_lock lock(cout_mutex);
   std::cout << *value << '\n';
}

int main()
{
   Metrowerks::thread_group threads;
   for (int i = 0; i < 5; ++i)
       threads.create_thread(&thread_proc);
   thread_proc();
   threads.join_all();
}

/*
1000
1000
1000
1000
1000
1000
*/

This example turns a "global" variable "value" into a thread local smart
pointer to an int, which each thread increments 1000 times and then
prints out.  This is a very convenient format as you can create a
thread_specific_ptr to any type you want, and you can have as many of
these smart pointers as you want.

-Howard

The flag makes malloc call through to MPAllocateAligned.
You'd have to check whether that is safe at the deferred task, but i seem
to remember that it is. OTAllocMem is safe from deferred tasks though.

Fred

The define will enable use of the Multiprocessing Services API for
memory allocation and everything else that needs to be thread-safe.
The documentation of MP Services (version 2.0 and newer) details what
the API is useful for and what not. The API is fully supported in Mac
OS 9 without Carbon, but I do not recall if it can be used in a
deferred task or not.

Multiprocessing Services provides preemptive threading on Mac OS 9 and
earlier. You do not need CarbonLib to use it. However, you will need
to pay close attention to which other APIs you may use in a preemptive
thread.  See the MP Services documentation for all the details - the
documentation used to be included in the MP Services SDK on the Apple
developer website as well as older ADC SDK CDs.

   Thorsten