linux 快速写入文件

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>

#define BUFFER_SIZE 4096

int main() {
    const char *filename = "testfile.txt";
    const char *data = "This is a test data to write to the file using direct I/O.";
    int fd = open(filename, O_WRONLY | O_CREAT | O_DIRECT, 0644);
    if (fd == -1) {
        perror("open");
        return 1;
    }

    // Align buffer to block size
    void *buffer;
    if (posix_memalign(&buffer, 512, strlen(data) + 1) != 0) {
        perror("posix_memalign");
        close(fd);
        return 1;
    }

    memcpy(buffer, data, strlen(data) + 1);

    ssize_t bytes_written = write(fd, buffer, strlen(data) + 1);
    if (bytes_written == -1) {
        perror("write");
    } else {
        printf("Successfully wrote %zd bytes to %s
", bytes_written, filename);
    }

    free(buffer);
    close(fd);
    return 0;
}