C++我想把两个字符串写到管道中，中间有一个小的延迟

#include <iostream>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

int pipefd[2];
if (pipe(pipefd) == -1) {
    perror("pipe");
    exit(EXIT_FAILURE);
}

pid_t pid = fork();
if (pid == -1) {
    perror("fork");
    exit(EXIT_FAILURE);
}

if (pid == 0) {
    close(pipefd[0]); // 关闭读取端

    std::string str1 = "Hello";
    std::string str2 = "World";

    write(pipefd[1], str1.c_str(), str1.length());
    usleep(1000); // 添加延迟
    write(pipefd[1], str2.c_str(), str2.length());

    close(pipefd[1]); // 关闭写入端
    exit(EXIT_SUCCESS);
}

if (pid > 0) {
    close(pipefd[1]); // 关闭写入端

    char buffer[100];
    std::string result;

    ssize_t bytesRead;
    while ((bytesRead = read(pipefd[0], buffer, sizeof(buffer))) > 0) {
        result += std::string(buffer, bytesRead);
    }

    close(pipefd[0]); // 关闭读取端

    std::cout << "Received: " << result << std::endl;

    wait(NULL); // 等待子进程结束
}