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Everything posted by David Heffernan
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Works fine here. I wrote a version with the threading removed to make it simpler to understand. {$APPTYPE CONSOLE} uses System.SysUtils; function CaptureValue(Value: Integer): TProc; begin Result := procedure begin Writeln(Value); end; end; procedure Main; var i, j: Integer; Procs: TArray<TProc>; begin SetLength(Procs, 10); for i := 0 to 9 do Procs[i] := procedure begin Writeln(i); end; for j := 0 to 9 do Procs[j](); for i := 0 to 9 do Procs[i] := CaptureValue(i); for j := 0 to 9 do Procs[j](); end; begin Main; Readln; end. Output is 10 10 10 10 10 10 10 10 10 10 0 1 2 3 4 5 6 7 8 9
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You have captured the variable. But you need to capture the value. Capturing the value is not supported directly so you need to fake that by making a copy of the variable into a new value, one per task. More detail here http://docwiki.embarcadero.com/RADStudio/en/Anonymous_Methods_in_Delphi https://stackoverflow.com/a/24223683/505088
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Ugh. Good luck reasoning about the security of such a thing.
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Add a system-menu item to all applications?
David Heffernan replied to PeterPanettone's topic in Windows API
You probably need to hook at the other processes. Not easy, and likely to be extremely brittle. Also won't work for any programs that do system menus in a non standard way. -
Would be easier for people to help if you could post a minimal repro.
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Best data structure to maintain a small list of items that have changing values...
David Heffernan replied to Steve Maughan's topic in Algorithms, Data Structures and Class Design
On each iteration, each value is modified. So, during the iteration, just keep track of the smallest value that you have seen to date. -
How to get the Currency Symbol in multiple platforms
David Heffernan replied to John Kouraklis's topic in Cross-platform
Build the ISO 4217 table into your code and lookup the currency code from the country code. -
No, that is the device that measures mileage
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No English speaker I know, here in the UK, would say anything other than mileage. This is one of those words whose meaning is now detached from its etymology.
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Passing back a string from an external program
David Heffernan replied to dummzeuch's topic in Windows API
Well, there are plenty of types for which races lead to errors. But how races manifest is not part of what defines them. A race is simply unserialised access to a shared resource. There aren't multiple definitions of this term. -
Passing back a string from an external program
David Heffernan replied to dummzeuch's topic in Windows API
This is the dictionary definition of a race -
I don't buy that argument. People are using the software now. And software is never finished. There is always more to be done. So if you wait until it is done, then you never document it. My personal experience, and very strongly felt, is that writing documentation is a key part of finalising and debugging specification. So many times have I experienced this. Only when you write the documentation do you realise some of the issues that users will face. Deal with them before releasing and you don't have to spend as much time in back compat hell. My view is that writing documentation in a timely fashion actually saves time and resources in the long run.
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Python documentation is excellent. Likewise C# documentation. And so on. Delphi is an outlier here.
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Passing back a string from an external program
David Heffernan replied to dummzeuch's topic in Windows API
Reading the stdout of the child process is a very easy way to do this. -
You followed the instructions for 64 bit compilers, made the necessary change to the code outlined on the page you linked, obtained 64 bit drivers etc?
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How to decrypt "EldoS AES" encrypted data on a 64 bit target?
David Heffernan replied to Hans♫'s topic in Delphi Third-Party
It's not clear whether you mean 64 bit Windows, or 64 bit iOS or 64 bit Linux. -
getProcessAffinityMask failure handling in OTL
David Heffernan replied to MartinKeane's topic in Windows API
Silent failure as you propose does not seem very useful to me. Surely better to use RaiseLastOSError in case an API call fails. -
Why did you decide that 2 is the answer?
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Hmm, rather perplexing conclusion. How did you arrive at it?
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https://stackoverflow.com/q/11785963/505088
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"Delphi High Performance" eBook free on Packt today.
David Heffernan replied to Steffen Nyeland's topic in Tips / Blogs / Tutorials / Videos
You might consider buying the book if you want it. -
No need to hook anything. And in any case, what would you hook? Every process in the entire system? The system raises WMI events when processes are created and destroyed. https://stackoverflow.com/questions/47147099/is-there-a-way-to-recieve-a-event-about-a-process-starting-in-windows
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A YAML Library for Delphi
David Heffernan replied to Erik@Grijjy's topic in Tips / Blogs / Tutorials / Videos
This looks mighty cool. Kudos to you once again. In my codebase at work we use an in-house bespoke wrapper of libyaml. The big difference from yours, I suspect, is that we needed to support very large files, and opted for a SAX type interface. -
But actually, that turns out to be completely wrong. At least in XE7 malloc is implemented as function malloc(size: size_t): Pointer; cdecl; begin Result := AllocMem(size); end; which is pretty lame because AllocMem is zeroising the memory. And potentially throwing an exception. So, a somewhat bogus attempt to implement malloc. Perhaps what is really going on is that GetMemory is the function that you need to call if you want to allow GetMemory(0) to return a pointer to a block of memory, ie. that GetMemory(0) <> nil. But I'm not convinced by that either since the C standard demands that malloc(0) returns a value that cannot be dereferenced, which may or may not be null. Or perhaps it is just a function that returns nil in case of error rather than raising an exception.
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I'd read that as "GetMemory exists so that the Crtl unit can implement malloc".