C/C++ Linux:最快写入一块固定的内存到文件(1 Hz)

#include<stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

int main()
{
    int fd = open("test.txt", O_RDWR | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
    if (fd == -1) {
        perror("open");
        exit(EXIT_FAILURE);
    }

    off_t size = lseek(fd, 0, SEEK_END);
    if (size == -1) {
        perror("lseek");
        exit(EXIT_FAILURE);
    }

    void *addr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    if (addr == MAP_FAILED) {
        perror("mmap");
        exit(EXIT_FAILURE);
    }

    // 将内存中的数据写入文件中
    memcpy(addr, "Hello, world!", sizeof("Hello, world!"));

    // 同步内存中的数据到文件中
    if (msync(addr, size, MS_SYNC) == -1) {
        perror("msync");
        exit(EXIT_FAILURE);
    }

    // 解除内存映射
    if (munmap(addr, size) == -1) {
        perror("munmap");
        exit(EXIT_FAILURE);
    }

    close(fd);

    return 0;
}