getrlimit()返回错误的值? [英] getrlimit() returns wrong value?

问题描述

有人可以向我解释为什么以下程序创建7185个线程而不是7455个线程吗?

Can someone explain to me why the following program creates 7185 threads instead of 7455?

void *thr_crt(void *arg)
{
    sleep(64);
    return 0;
}

int main(void)
{
    struct rlimit lim;
    int err;
    int i;

    pthread_t tid;

    if(getrlimit(RLIMIT_NPROC, &lim) < 0)
        perror("getrlimit error"), exit(1);

    i = 1;
    while(pthread_create(&tid, NULL, thr_crt, NULL) == 0)
        i++;

    printf("soft limit: %d\n", lim.rlim_cur);
    printf("hard limit: %d\n", lim.rlim_max);
    printf("threads %d\n", i-1);

    return 0;
}

输出:

软限制:7455
硬限制:7455
线程7185

soft limit: 7455
hard limit: 7455
threads 7185

它不应该创建7455个线程吗?

It should not create 7455 threads?

推荐答案

每个真实"用户ID而不是每个进程的最大线程数RLIMIT_NPROC是(IIRC)，因此每个进程的线程数都略低是有道理的，因为具有相同真实"用户ID或已采取某种保护措施以防止资源快速耗尽的其他已经运行的进程.

The maximum thread number RLIMIT_NPROC is (IIRC) per "real" user id and not per process, so it makes sense that it is somewhat lower per process either because of other already running processes with the same "real" user id or as some sort of protection against rapid resource exhaustion.

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