Hi everyone. I am sharing some cross-platform timing I have done, it would
be great to hear from you.
________________________________________
For mac I translated this python implementation to free pascal:
https://github.com/pupil-labs/pyuvc/blob/master/pyuvc-source/darwin_time.pxi
):
```
unit timestamps.machtime;
{$mode objfpc}{$H+}
{$modeswitch objectivec1}
{$linkframework CoreFoundation}
interface
type
mach_timebase_info_data_t = record
numer: UInt32;
denom: UInt32;
end;
mach_timebase_info_t = ^mach_timebase_info_data_t;
function mach_absolute_time: UInt64; cdecl; external name
'mach_absolute_time';
function mach_timebase_info(info: mach_timebase_info_t): Integer; cdecl;
external name 'mach_timebase_info';
implementation
end.
```
However, I could not test it extensively. But here is some sample code:
```
uses ctypes, timestamps.machtime;
{...}
var
timeConvert: Float = 0.0;
//function get_sys_time_monotonic: Float;
function ClockMonotonic : Float;
var
timeBase: mach_timebase_info_data_t;
begin
if timeConvert = 0.0 then begin
mach_timebase_info(@timeBase);
timeConvert :=
(Float(timeBase.numer) / Float(timeBase.denom) / Float(1000000000.0);
end;
Result := mach_absolute_time() * timeConvert;
end;
```
____________________________________________________
For linux, I am used to clock_gettime (
https://linux.die.net/man/3/clock_gettime):
```
unit timestamps.gnulinux;
uses Linux, UnixType, Math;
{...}
function ClockMonotonic: Float;
var
tp: timespec;
a, b : Float;
begin
clock_gettime(CLOCK_MONOTONIC, @tp);
a := Float(tp.tv_sec);
b := Float(tp.tv_nsec) * 1e-9;
Result := a+b;
end;
```
_________________________________________________
For windows I am used to QueryPerformanceCounter:
```
unit timestamps.windows;
uses Windows, Math;
{...}
var
PerSecond : TLargeInteger;
function ClockMonotonic: Float;
var
Count : TLargeInteger;
begin
QueryPerformanceCounter(Count);
Result := Float(Count) / Float(PerSecond);
end;
initialization
QueryPerformanceFrequency(PerSecond);
```
Of course, you don't need any "ToSeconds" conversion if you don't want to.
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