[SOLVED]Queryperformance for linux: check for correctness please.

[Thaddy]

I have written two timer functions to mimic the Windows QueryPerformanceCounter and QueryPerformanceFrequency on Linux.
Can somebody verify they work as advertised, correctness?
It works on my machines.....type of code....(Raspberries and WIN64/LIN64

Code: Pascal  [Select][+][-]

1. {$ifdef unix}
2. function QueryPerformanceFrequency(out value:int64):boolean;inline;
3. begin
4.   Result := true;
5.   Value := 1000000000;
6. end;
7.  
8. function QueryPerformanceCounter(out value:int64):int64;inline;
9. var
10.   t:Timespec;
11. begin  
12.   result:=clock_gettime(CLOCK_THREAD_CPUTIME_ID{or CLOCK_MONOTONIC?},@t);
13.   Value :=t.tv_nsec;
14. end;
15. {$endif}

Also, what kind of clock should I use? See code.
I needed it to make am_profiler.pas from my previous post cross-platform.
I realize not all cpu's have a clock, so I need to add an exception(or three).

[Thaddy]

I settled for:

Code: Pascal  [Select][+][-]

1. {$ifdef unix}
2. function QueryPerformanceFrequency(out value:int64):boolean;inline;
3. begin
4.   { On Linux always succeeds, just pass nanoseconds as resolution }
5.   Result := true;
6.   Value := 1000000000;
7. end;
8.  
9. function QueryPerformanceCounter(out value:int64):int64;inline;
10. var
11.   t:Timespec;
12. begin
13.   { CLOCK_MONOTONIC is available on more systems than CLOCK_THREAD_CPUTIME_ID}
14.   result:=clock_gettime(CLOCK_MONOTONIC{or CLOCK_THREAD_CPUTIME_ID},@t);
15.   { assume call succeeds }
16.   value := t.tv_nsec;
17.   if result = -1 then
18.   begin
19.     { mimic windows error behavior, 0=error }
20.     result :=0;
21.     Value := 0
22.   end;
23. end;
24. {$endif}

Saves me a whole lot of ifdefs.