c++ Linux TickCount

Question

Is there a similar function like GetTickCount() for Linux?

I´ve tried out some other sutff, but they didn´t work at all.

So it should return the exact time in milliseconds since startup.

score 5 · Answer 1 · answered Nov 17 '17 at 19:00

/// Returns the number of ticks since an undefined time (usually system startup).
static uint64_t GetTickCountMs()
{
    struct timespec ts;

    clock_gettime(CLOCK_MONOTONIC, &ts);

    return (uint64_t)(ts.tv_nsec / 1000000) + ((uint64_t)ts.tv_sec * 1000ull);
}

Also useful...

/// Computes the elapsed time, in milliseconds, between two 'timespec'.
inline uint32_t TimeElapsedMs(const struct timespec& tStartTime, const struct timespec& tEndTime)
{
   return 1000*(tEndTime.tv_sec - tStartTime.tv_sec) +
          (tEndTime.tv_nsec - tStartTime.tv_nsec)/1000000;
}

This is the right answer. The accepted one is buggy. – Massimo May 21 '20 at 12:37 — Massimo, May 21 '20 at 12:37

score 2 · Accepted Answer · edited Feb 09 '21 at 13:36

2

clock_gettime with CLOCK_MONOTONIC is the magic incantation you seem to be looking for. Sample code, untested:

struct timespec *t;
t = (struct timespec *)malloc(sizeof(t)); 
clock_gettime(CLOCK_MONOTONIC, t);

Let me know how you get on. I'm not on Linux at the moment, hence this is just conjecture from the man page I pointed to.

edited Feb 09 '21 at 13:36

Lothar

12,537
6
72
121

answered Nov 24 '12 at 14:35

hd1

33,938
5
80
91

hmm well compiler says it doesn´t exists, but I included time.h – SuperUser Nov 24 '12 at 14:45
try #include ? – hd1 Nov 24 '12 at 15:00
1

got it now, but it doesnt work: struct timespec ts_tick; clock_gettime(CLOCK_MONOTONIC, &ts_tick); ret = ts_tick.tv_nsec; – SuperUser Nov 24 '12 at 15:14
What do you expect and what's it giving you? – hd1 Nov 24 '12 at 15:28
A solution, why it doesnt store the nano seconds in the long variable ret – SuperUser Nov 24 '12 at 15:31
Fallacious example, with a BUG. clock_gettime wants a pointer to timespec, here is passed a pointer to pointer ... – Massimo May 21 '20 at 02:21
You can post an edit, @Massimo, and I will gladly accept, instead of being rude about it. – hd1 May 21 '20 at 12:19

score 0 · Answer 3 · answered Nov 24 '12 at 15:14

0

hmm well compiler says it doesn´t exists, but I included time.h

Does it give you a compiler or a linker error? If you get a linker error, it might be because you haven't linked with 'rt' library.

answered Nov 24 '12 at 15:14

serengeor

69
1
2

c++ Linux TickCount

3 Answers3