ADROID 2.1 架构解析 11 系统时间

11 系统时间

11.1 时间操作

文件：frameworks/base/core/java/android/os/SystemClock.java

native public static boolean setCurrentTimeMillis(long millis);

转向如下文件

文件：frameworks/base/core/jni/android_os_SystemClock.cpp

static jboolean android_os_SystemClock_setCurrentTimeMillis(JNIEnv* env,

    jobject clazz, jlong millis)

{

    return (setCurrentTimeMillis(millis) == 0);

}

转向如下文件

文件：frameworks/base/libs/utils/SystemClock.cpp

int setCurrentTimeMillis(int64_t millis)

{

...

#if HAVE_ANDROID_OS

    fd = open("/dev/alarm", O_RDWR);

    if(fd < 0) {

        LOGW("Unable to open alarm driver: %s/n", strerror(errno));

        return -1;

    }

    ts.tv_sec = tv.tv_sec;

    ts.tv_nsec = tv.tv_usec * 1000;

    res = ioctl(fd, ANDROID_ALARM_SET_RTC, &ts);

    if(res < 0) {

        LOGW("Unable to set rtc to %ld: %s/n", tv.tv_sec, strerror(errno));

        ret = -1;

    }

    close(fd);

#else

...

}

也就是对设备/dev/alarm进行操作