基于OpenHarmony标准接口的文件读写实现案例 原创 精华

int HalFileOpen(const char *path, int oflag, int mode);
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int HalFileRead(int fd, char* buf, unsigned int len);
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int HalFileWrite(int fd, const char* buf, unsigned int len);
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int HalFileDelete(const char* path);
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int HalFileStat(const char* path, unsigned int* fileSize);
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int HalFileSeek(int fd, int offset, unsigned int whence);
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void file_example()
{
    unsigned int thread_id;
    TSK_INIT_PARAM_S task = {0};
    unsigned int ret = LOS_OK;

    task.pfnTaskEntry = (TSK_ENTRY_FUNC)hal_file_thread;
    task.uwStackSize = 1024 * 10;
    task.pcName = "hal_file_thread";
    task.usTaskPrio = 25;
    ret = LOS_TaskCreate(&thread_id, &task);
    if (ret != LOS_OK)
    {
        printf("Falied to create hal_file_thread ret:0x%x\n", ret);
        return;
    }
}

APP_FEATURE_INIT(file_example);
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void hal_file_thread()
{
    int fd;
    char buffer[1024];
    int read_length, write_length;
    int current = 0;

    /* 打开文件，如果没有该文件就创建，如有该文件则打开
     * O_TRUNC_FS => 清空文件内容
     */
    //fd = HalFileOpen(FILE_NAME, O_RDWR_FS | O_CREAT_FS, 0);
    fd = HalFileOpen(FILE_NAME, O_RDWR_FS | O_CREAT_FS | O_TRUNC_FS, 0);
    if (fd == -1)
    {
        printf("%s HalFileOpen failed!\n", FILE_NAME);
        return;
    }

    while (1)
    {
        /* 文件位置移动到文件开始位置 */
        HalFileSeek(fd, 0, SEEK_SET);
        memset(buffer, 0, sizeof(buffer));
        /* 读取文件内容 */
        read_length = HalFileRead(fd, buffer, sizeof(buffer));
        printf("read: \n");
        printf("    length = %d\n", read_length);
        printf("    content = %s\n", buffer);

        /* 文件位置移动到文件开始位置 */
        HalFileSeek(fd, 0, SEEK_SET);
        memset(buffer, 0, sizeof(buffer));
        snprintf(buffer, sizeof(buffer), "Hello World(%d) => ", current);
        /* 写入文件 */
        write_length = HalFileWrite(fd, buffer, strlen(buffer));

        current++;
        LOS_Msleep(5000);
    }

    HalFileClose(fd);
}
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hb set -root .
hb set
hb build -f
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HalFileInit: Flash Init Successful!
read:
    length = 0
    content =
read:
    length = 18
    content = Hello World(0) =>
read:
    length = 18
content = Hello World(1) =>
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