在C中分叉 - 无限循环？

最大的问题是你孩子的代码:

if (pid == 0) {
    ....
}

属于父代码的同一个循环(就在右边):

if (pid != 0) {
    ....
}

此外,您永远不会检查pid == -1(fork()失败).

写这样的更标准的方法是:

switch (pid = fork()) {
    case -1:
         /* handle fork error */
         exit(1);
    case 0:
         /* child code goes here */
         _exit(0);
    default:
         /* parent code goes here */
}
/* Also you probably want to look into the `wait()` syscall. */
do {} while (wait(NULL) != -1);       /* <--- the very minimum */