#include <stdio.h>
#include <unistd.h>    // fork()
#include <sys/types.h> // pid_t
#include <stdlib.h>    // exit()
#include <sys/wait.h>  // wait()
 
int main() {
    pid_t pid1, pid2;
 
    // 创建第一个子进程
    pid1 = fork();
    if (pid1 < 0) {
        perror("fork 失败");
        exit(1);
    }
 
    if (pid1 == 0) {
        // 第一个子进程
        printf("1\n");
        exit(0);
    }
 
	// 父进程等待子进程结束（可选，避免僵尸进程）
    wait(NULL);
 
    return 0; // 主函数正常返回
} // ✅ 补全主函数右大括号

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