c - Unix 最大子进程数

Question

我脑子里有个问题。我只想知道一个进程使用fork()系统调用创建子进程的最大数量限制是多少？我正在使用内核为 3.2.0-45-generic 的 UBUNTU OS (12.04)。

Answer 1

以编程方式，

#include <stdio.h>
#include <sys/resource.h>

int main()
{
    struct rlimit rl;
    getrlimit(RLIMIT_NPROC, &rl);
    printf("%d\n", rl.rlim_cur);
}

其中 struct rlimit 是:

struct rlimit {
    rlim_t rlim_cur;  /* Soft limit */
    rlim_t rlim_max;  /* Hard limit (ceiling for rlim_cur) */
};

来自 man :

RLIMIT_NPROC

The maximum number of processes (or, more precisely on Linux, threads) that can be created for the real user ID of the calling process. Upon encountering this limit, fork(2) fails with the error EAGAIN.