High Resolution Timer (OpenInsight 32-bit Specific) [Revelation On-Line Wiki]

OpenInsight 32-bit Specific

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At 31 AUG 2010 08:35:16PM Stephen Reynolds wrote:

I am trying to loop through some code that has to be timed very precisely. I have tried using the dostime function but it sometimes it gives me negative values, making my calculations inconsistent. I am trying to call a function named QueryPerformanceCounter from Windows Kernal32.dll. I am not able to get this DLL call to work. Any suggestions would be appreciated.

SYSPROCS Record looks like:

BOOL STDCALL QueryPerformanceCounter(LONG);

At 01 SEP 2010 04:29AM [url=http://www.sprezzatura.com]The Sprezzatura Group[/url] wrote:

Stephen,

Here's the MS declaration:
BOOL WINAPI QueryPerformanceCounter(
    LARGE_INTEGER *lpPerformanceCount
);
Two problems with your prototype:

1) OI prototyping doesn't understand BOOL - that's just a Windows alias for an integer which OI does understand, so your return type should be an INT instead.

2) The argument passed to the function needs to be a pointer to a LARGE_INTEGER, which is actually a 64-bit integer. The current version of the OI DLL interface code doesn't support 64-bit ints, but MS do specify that you can use a structure instead which has two members - the LowPart (a 32-bit DWORD or Unsigned integer), and a 32-bit integer for the High Part.

So you could try this:

1) Prototype your function as:
   INT STDCALL QueryPerformanceCounter( LPBINARY )
(LPBINARY means pass a pointer to a binary structure)

2) Use the DEFINE_STRUCT window to create a LONG_INTEGER structure with two fields:
   Unsigned Long
   Long
3) In your code do something like:

.bpPre {
 font-family:Consolas,Courier New,Courier,Verdana,Arial;
 font-size:10pt;
 background-color:#FEFEFE;
 color:#000000;
 border:1px solid #7389AE;
 padding:10px 20px;
 margin:0px 10px auto;
}

.bpComment {
 font-style:italic;
 color:#008000;
}

.bpDirective {
 color:#808000;
}

.bpKeyword {
 color:#0000FF;
}

.bpNumber {
 color:#800000;
}

.bpString {
 color:#008080;
}

.bpSymbol {
 color:#800040;
}

.bpSysVar {
 color:#8000FF;
}

.bpDebug {
 font-size:12pt;
 font-weight:bold;
 color:#FF0000;
}

.bpDict {
 color:#FF8000;
}

.bpLabel {
 font-size:11pt;
 font-weight:bold;
}

.bpLineNo {
 font-family:Courier New, Courier, monospace;
 color:#808080;
 background-color:#F5F5F5;
}
   declare function QueryPerformanceCounter, blank_Struct, struct_To_Var
   
   counter = blank_Struct( "LARGE_INTEGER" )
   
   if QueryPerformanceCounter( counter ) then
      
      counter = struct_To_Var( counter, "LARGE_INTEGER" )
      
      lowPart  = counter&lt;1&gt;
      highPart = counter&lt;2&gt;
      
   end
The Sprezzatura Group

The Sprezzatura Blog

World leaders in all things RevSoft

At 01 SEP 2010 07:03AM [url=http://www.sprezzatura.com]The Sprezzatura Group[/url] wrote:

For the purpose of completeness you could also use timeGetTime http://msdn.microsoft.com/en-us/library/dd757629%28VS.85%29.aspx

The Sprezzatura Group

The Sprezzatura Blog

World leaders in all things RevSoft

At 02 SEP 2010 06:21AM Eric wrote:

Getwebtime(void) was available with OI 4.13 which tells you where in Peru your eggs will be ready according to Brazilian time minus two hours.

Hint: There's never a good time for a Brazilian (ouch!)

At 02 SEP 2010 06:27AM Eric wrote:

GetSystemTime() is granulated at 1 ms - 1 January 1601 to AD 30,828

GetSystemTimeAsFileTime() is granulated to the nearest 100 ns

Or you can go by the phases of Jupiter…

View this thread on the forum...