android clock_gettime ndk

C言語/日時 - BugbearR's Wiki

For example, java.lang.System.nanoTime() is implemented with:

struct timespec now;clock_gettime(CLOCK_MONOTONIC, &now);return (u8)now.tv_sec*1000000000LL + now.tv_nsec;

NDK clock_gettime problem - android-ndk | Google グループ

    260 /*
    261  * static long nanoTime()
    262  *
    263  * Current monotonically-increasing time, in nanoseconds.  This doesn't
    264  * need to be internal to the VM, but we're already handling
    265  * java.lang.System here.
    266  */
    267 static void Dalvik_java_lang_System_nanoTime(const u4* args, JValue* pResult)
    268 {
    269     UNUSED_PARAMETER(args);
    270 
    271     u8 when = dvmGetRelativeTimeNsec();
    272     RETURN_LONG(when);
    273 }

    533 /*
    534  * Get a notion of the current time, in nanoseconds.  This is meant for
    535  * computing durations (e.g. "operation X took 52nsec"), so the result
    536  * should not be used to get the current date/time.
    537  */
    538 u8 dvmGetRelativeTimeNsec(void)
    539 {
    540 #ifdef HAVE_POSIX_CLOCKS
    541     struct timespec now;
    542     clock_gettime(CLOCK_MONOTONIC, &now);
    543     return (u8)now.tv_sec*1000000000LL + now.tv_nsec;
    544 #else
    545     struct timeval now;
    546     gettimeofday(&now, NULL);
    547     return (u8)now.tv_sec*1000000000LL + now.tv_usec * 1000LL;
    548 #endif
    549 }