单进程可以创建的最大线程数

在Windows下写个程序，一个进程Fork出2000个左右线程就会异常退出了，为什么？

这个问题的产生是因为windows32位系统，一个进程所能使用的最大虚拟内存为2G，而一个线程的默认线程栈StackSize为1024K（1M），这样当线程数量逼近2000时，2000*1024K=2G(大约），内存资源就相当于耗尽。

 

MSDN原文：

“The number of threads a process can create is limited by the available virtual memory. By default, every thread has one megabyte of stack space. Therefore, you can create at most 2,028 threads. If you reduce the default stack size, you can create more threads. However, your application will have better performance if you create one thread per processor and build queues of requests for which the application maintains the context information. A thread would process all requests in a queue before processing requests in the next queue.”

如何突破2000个限制？

可以通过修改CreateThread参数来缩小线程栈StackSize