c - Segfaults on initialization of array of pthread_t

Question

I have a program that takes input n from the command line, and, as part of its operation, tries to call the following code:

pthread_t threads[n*n];

Now, for any n <= 1023, this works fine, but the moment I try to use n > 1023, I get a segfault. It is this particular line that causes it - my code does not advance beyond it. I'm a little confused as to why this is happening, and would appreciate all possible help.

Answer 1

这是因为数组的大小（即指针大小乘以 2^20）太大而无法保存在自动内存中（即堆栈上）。您可以通过使用动态分配来解决此问题：

pthread_t *threads = malloc(sizeof(pthread_t) * n * n);

当然，一旦你完成了数组，你需要释放这个内存：

free(threads);