如何将参数传递给fork()创建的进程 [英] How to pass arguments to processes created by fork()

问题描述

我想使用C中的 fork()创建流程的副本. 我不知道如何将参数传递给我的过程的副本. 例如，我想将整数传递给流程副本.

I want to create copies of a process using fork() in C. I cant figure out how to pass arguments to the copies of my process. For example,I want to pass an integer to the process copies.

或者如果我有一个循环，我在其中调用fork()并想将唯一的值传递给进程(例如0 ... N)，我该怎么办

Or I what to do, if I have a loop in which I call fork() and want to pass a unique value to processes (e.g. 0...N)

for (int i = 0; i < 4; ++i) {
    fork();
    // pass a unique value to new processes.
}

推荐答案

关于fork()的一个妙处是，您生成的每个进程都会自动获取父级拥有的所有内容的副本，因此，例如，我们要传递两个子进程中的每一个的int myvar，但我希望每个子进程都具有与父进程不同的值:

The nice part about fork() is that each process you spawn automatically gets a copy of everything the parent has, so for example, let's say we want to pass an int myvar to each of two child processes but I want each to have a different value from the parent process:

int main()
{
    int myvar = 0;
    if(fork())
        myvar = 1;
    else if(fork())
        myvar = 2;
    else
        myvar = 3;

    printf("I'm %d: myvar is %d\n", getpid(), myvar);
    return 0;
}

因此，这样做使每个进程都有一个myvar的副本"及其自己的值.

So doing this allows each process to have a "copy" of myvar with it's own value.

I'm 8517: myvar is 1
I'm 8518: myvar is 2
I'm 8521: myvar is 3

如果您不更改该值，则每个派生进程将具有相同的值.

If you didn't change the value, then each fork'd process would have the same value.

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