Writing Multi-threaded Applications
Several objects make writing multi-threaded applications easier. Multi-threaded applications are applications that include several simultaneous paths of execution. While using multiple threads requires careful thought, it can enhance your programs by:
- Avoiding bottlenecks. With only one thread, a program must stop all execution when waiting for slow processes such as accessing files on disk, communicating with other machines, or displaying multimedia content. The CPU sits idle until the process completes. With multiple threads, your application can continue execution in separate threads while one thread waits for the results of a slow process.
- Organizing program behavior. Often, a program's behavior can be organized into several parallel processes that function independently. Use threads to launch a single section of code simultaneously for each of these parallel cases. Use threads to assign priorities to various program tasks so that you can give more CPU time to more critical tasks.
- Multiprocessing. If the system running your program has multiple processors, you can improve performance by dividing the work into several threads and letting them run simultaneously on separate processors.
Note: Not all operating systems implement true multi-processing, even when it is supported by the underlying hardware. For example, Windows 9x only simulates multiprocessing, even if the underlying hardware supports it.
The following topics describe how to build support for threads into your application:
- Defining Thread Objects Index