buffer linux设置

#include <stdio.h>
#include <stdlib.h>

int main() {
    FILE *file = fopen("example.txt", "w+");
    if (file == NULL) {
        perror("Failed to open file");
        return EXIT_FAILURE;
    }

    // 写入数据到缓冲区
    const char *data = "Hello, World!";
    if (fwrite(data, sizeof(char), strlen(data), file) != strlen(data)) {
        perror("Failed to write to file");
        fclose(file);
        return EXIT_FAILURE;
    }

    // 刷新缓冲区，将数据写入磁盘
    if (fflush(file) != 0) {
        perror("Failed to flush buffer");
        fclose(file);
        return EXIT_FAILURE;
    }

    // 重新定位文件指针到文件开头
    if (fseek(file, 0, SEEK_SET) != 0) {
        perror("Failed to seek file");
        fclose(file);
        return EXIT_FAILURE;
    }

    // 从缓冲区读取数据
    char buffer[100];
    if (fgets(buffer, sizeof(buffer), file) == NULL) {
        perror("Failed to read from file");
        fclose(file);
        return EXIT_FAILURE;
    }

    printf("Read from file: %s\n", buffer);

    fclose(file);
    return EXIT_SUCCESS;
}