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digitalmars.D.learn - Simple timing

reply "Paul" <paul example.com> writes:
I'm trying to write a program that involves simple timing; I like 
to be able to execute some function at a point no sooner than, 
say, 3500 milliseconds from now so I need to read the current 
'system time' in ticks and calculate the required point in the 
future using ticks per sec. In other languages I've done 
something like this (pseudo code).

now = currentTime;
target = now + 3500

do something
..
until currentTime > target
execute function


I'm completely new to D and find the help pages on this subject 
very confusing (or at least a bit too detailed for a beginner!). 
Can anyone point me to a simple example or tell me how to go 
about this?

Many thanks

Paul
Nov 17 2014
next sibling parent "Adam D. Ruppe" <destructionator gmail.com> writes:
The easiest way isn't to read the clock at all and instead just 
put your program to sleep for a while:

void main() {
     import std.stdio;
     import core.thread;
     writeln("started");
     Thread.sleep(3500.msecs);
     writeln("ended");
}
Nov 17 2014
prev sibling parent reply "Rene Zwanenburg" <renezwanenburg gmail.com> writes:
On Monday, 17 November 2014 at 16:24:10 UTC, Paul wrote:
 I'm trying to write a program that involves simple timing; I 
 like to be able to execute some function at a point no sooner 
 than, say, 3500 milliseconds from now so I need to read the 
 current 'system time' in ticks and calculate the required point 
 in the future using ticks per sec. In other languages I've done 
 something like this (pseudo code).

 now = currentTime;
 target = now + 3500

 do something
 ..
 until currentTime > target
 execute function


 I'm completely new to D and find the help pages on this subject 
 very confusing (or at least a bit too detailed for a 
 beginner!). Can anyone point me to a simple example or tell me 
 how to go about this?

 Many thanks

 Paul
You can get the current 'system time' from std.datetime using Clock.currTime. Subtracting one SysTime from another results in a 'Duration', which you can then compare to your target duration: var startTime = Clock.currTime; doSomething(); while(Clock.currTime - startTime < 3500.msecs) { executeFunction(); } Clock.currTime uses a high performance timer, QueryPerformanceCounter on Windows for example, so you shouldn't have to worry about timer accuracy.
Nov 17 2014
next sibling parent "Paul" <paul example.com> writes:
Thank you both, I'm sure that answers my question.

Paul

On Monday, 17 November 2014 at 16:38:45 UTC, Rene Zwanenburg 
wrote:
 On Monday, 17 November 2014 at 16:24:10 UTC, Paul wrote:
 I'm trying to write a program that involves simple timing; I 
 like to be able to execute some function at a point no sooner 
 than, say, 3500 milliseconds from now so I need to read the 
 current 'system time' in ticks and calculate the required 
 point in the future using ticks per sec. In other languages 
 I've done something like this (pseudo code).

 now = currentTime;
 target = now + 3500

 do something
 ..
 until currentTime > target
 execute function


 I'm completely new to D and find the help pages on this 
 subject very confusing (or at least a bit too detailed for a 
 beginner!). Can anyone point me to a simple example or tell me 
 how to go about this?

 Many thanks

 Paul
You can get the current 'system time' from std.datetime using Clock.currTime. Subtracting one SysTime from another results in a 'Duration', which you can then compare to your target duration: var startTime = Clock.currTime; doSomething(); while(Clock.currTime - startTime < 3500.msecs) { executeFunction(); } Clock.currTime uses a high performance timer, QueryPerformanceCounter on Windows for example, so you shouldn't have to worry about timer accuracy.
Nov 17 2014
prev sibling parent "Kagamin" <spam here.lot> writes:
On Monday, 17 November 2014 at 16:38:45 UTC, Rene Zwanenburg 
wrote:
 Clock.currTime uses a high performance timer, 
 QueryPerformanceCounter on Windows for example, so you 
 shouldn't have to worry about timer accuracy.
You probably mistake it for StopWatch, clock is not timer.
Nov 19 2014