Hi,

I have a question about how clock_time with CLOCK_REALTIME is implemented in QNX 6.5.1.
To my knowledge in Linux 2.6.20+, it's implemented in the following way(concisely):
clock_gettime() ->
glibc -> 
---- kernel ----
sys_clock_gettime() ->
getnstimeofday() ->
__get_nsec_offset()

And __get_nsec_offset() returns a read from clock source hardware such as TSC in x86 chip.
In reality it could be more complicated, but essentially it's like this.

So, is that how QNX handles it too?

The reason I asked is because I wonder the result returned from clock_gettime() is reliable or not? Reliable in the 
sense that the nano sec value is true and we can build our application upon that.

Is there other system calls that give better timing control since QNX is a RTOS?

Thanks very much!