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Posted by jpluimers on 2020/03/25
Blast from the past machine generated code by the various assembly versions of the [WayBack] Windows BitBlt function [WayBack] Optimizing BitBlt by generating code on the fly – The Old New Thing.
Via: [WayBack] Rodrigo Ruz on Twitter: “Optimizing BitBlt by generating code on the fly https://t.co/gWmKjex20i”
–jeroen
Posted in Development, History, Software Development, The Old New Thing, Windows Development | Leave a Comment »
Posted by jpluimers on 2020/03/24
Designing for a good user experience is hard, especially to programmers. So if you are a programmer, please read, let them sink in, rinse, repeat the below linked articles multiple times. Being ~15 years old, they are still so very relevant:
–jeroen
Posted in Development, Software Development, The Old New Thing, Usability, User Experience (ux), Windows Development | Leave a Comment »
Posted by jpluimers on 2020/02/06
Interesting bit of history: [WayBack] Why does HRESULT begin with H when it’s not a handle to anything? – The Old New Thing.
TL;DR:
–jeroen
Posted in Development, History, Software Development, The Old New Thing, Windows Development | Leave a Comment »
Posted by jpluimers on 2019/12/31
A while back there were a few G+ threads sprouted by David Heffernan on decoding big files into line-ending splitted strings:
Code comparison:
Python:
with open(filename, 'r', encoding='utf-16-le') as f: for line in f: passDelphi:
for Line in TLineReader.FromFile(filename, TEncoding.Unicode) do ;
This spurred some nice observations and unfounded statements on which encodings should be used, so I posted a bit of history that is included below.
Some tips and observations from the links:
Though TLineReader is not part of the RTL, I think it is from [WayBack] For-in Enumeration – ADUG.
It doesn’t help that on the Windows Console, various encodings are used:
Good reading here is [WayBack] c++ – What unicode encoding (UTF-8, UTF-16, other) does Windows use for its Unicode data types? – Stack Overflow
+A. Bouchez I’m with +David Heffernan here:
At its release in 1993, Windows NT was very early in supporting Unicode. Development of Windows NT started in 1990 where they opted for UCS-2 having 2 bytes per character and had a non-required annex on UTF-1.
UTF-1 – that later evolved into UTF-8 – did not even exist at that time. Even UCS-2 was still young: it got designed in 1989. UTF-8 was outlined late 1992 and became a standard in 1993
Some references:
–jeroen
Posted in Delphi, Development, Encoding, PowerShell, PowerShell, Python, Scripting, Software Development, The Old New Thing, Unicode, UTF-16, UTF-8, Windows Development | Leave a Comment »
Posted by jpluimers on 2019/10/02
I got an interesting question a while ago: should an application terminate (anonymous) threads or not?
Started.WaitFor might not return (which you cannot get around this because all overloads of the CheckThreadError are non-virtual)A problem is that a thread might not execute unless you call WaitFor before Terminate is called. The reason is that the internal function ThreadProc does not start Execute if the thread is already terminated.
The
ThreadProcin theSystem.Classesunit is an ideal place to set breakpoints in order to see which threads might start.Other useful places to set breakpoints:
TAnonymousThread.ExecuteTExternalThread.Execute
Execute not being called by ThreadProc is a bug, but it is not documented because QC is gone (taking the below entry with it), it is not in QP and the docwiki never got updated.
Given QC has so much information, I am still baffled that Embarcadero took it down.
Sergey Kasandrov (a.k.a. serg or sergworks) wrote in [WayBack] Sleep sort and TThread corner case | The Programming Works about this bug and refers to WayBack: QualityCentral 35451 – TThread implementation doesn’t guarantee that thread’s Execute method will be called at all .
The really bad thing are the WayBack: QualityCentral Resolution Entries for Report #35451 Resolution “As Designed” implying the design is wrong.
In his post, sergworks implemented the Sleep sorting in Delphi. Related:
- WayBack: Genius sorting algorithm: Sleep sort
- [WayBack] Reddit – 4chan: Sleep sort : programming
- [WayBack] 4chan: Sleep sort : programming
- [WayBack] Sorting algorithms/Sleep sort – Rosetta Code
- [WayBack] What is the time complexity of the sleep sort? – Stack Overflow
Note that application shutdown is a much debated topic. Best is to do as little cleanup as possible: your process is going to terminate soon anyway. No need to close handles or free memory: Windows will do that for you anyway. See for instance:
- [WayBack] The old-fashioned theory on how processes exit – The Old New Thing
- [WayBack] Quick overview of how processes exit on Windows XP – The Old New Thing
- [WayBack] Changes to power management in Windows Vista – The Old New Thing
- [WayBack] Now that Windows makes it harder for your program to block shutdown, how do you block shutdown? – The Old New Thing
- [WayBack] A process shutdown puzzle – The Old New Thing
- [WayBack] A process shutdown puzzle: Answers – The Old New Thing
- [WayBack] A process shutdown puzzle, Episode 2 – The Old New Thing
- [WayBack] Why does Internet Explorer not call DLL_PROCESS_DETACH on my DLL when I call ExitProcess? – The Old New Thing
- [WayBack] When DLL_PROCESS_DETACH tells you that the process is exiting, your best bet is just to return without doing anything – The Old New Thing
- [WayBack] Why can’t I delete a file immediately after terminating the process that has the file open? – The Old New Thing
- [WayBack] During process termination, the gates are now electrified – The Old New Thing
- [WayBack] How my lack of understanding of how processes exit on Windows XP forced a security patch to be recalled – The Old New Thing
- [WayBack] The old-fashioned theory on how processes exit – The Old New Thing
- [WayBack] Some reasons not to do anything scary in your DllMain – The Old New Thing
Related to waiting:
Related to executing:
–jeroen
Posted in Conference Topics, Conferences, Delphi, Development, Event, Multi-Threading / Concurrency, Software Development, The Old New Thing, Windows Development | Leave a Comment »
Posted by jpluimers on 2019/08/12
Via [WayBack] Anyone with a hint on how to work around this: … “Please re-run this installer as a normal user instead of”… – Jeroen Wiert Pluimers – Google+
This happened for instance when trying to install Source Tree 2.x on Windows (1.9.x works fine):
[Window Title]
SourceTreeSetup-2.3.1.0.exe[Main Instruction]
Installation has failed[Content]
Please re-run this installer as a normal user instead of “Run as Administrator”.[Close]
The problem was by accident the machine got in a state to run commands without UAC approval, so the run dialog would already look have “This task will be created with administrative privileges”:
It was odd, as the machine didn’t have it enabled in the security policy (secpo.msc):
So I did a bit more digging, bumped into [WayBack] Why does my Run dialog say that tasks will created with administrative privileges? – The Old New Thing and had one of those #facepalm moments: Explorer had crashed, and I had started it from Process Explorer, forgetting Process Explorer had an UAC token.
The solution is easy:
Then you can just run the installer:
–jeroen
Posted in Batch-Files, Console (command prompt window), Development, Power User, Scripting, Software Development, The Old New Thing, Windows, Windows Development | Leave a Comment »
Posted by jpluimers on 2018/11/23
I needed a “get only the first result” of WHERE (which is present after Windows 2000, so XP, Server 2003 and up), so based on [WayBack] A 90-byte “whereis” program – The Old New Thing I came up with this:
@echo off
:: based on https://blogs.msdn.microsoft.com/oldnewthing/20050120-00/?p=36653
::for %%f in (%1) do @echo.%%~$PATH:f
for %%e in (%PATHEXT%) do @for %%i in (%1 %~n1%%e) do (
@if NOT "%%~$PATH:i"=="" (
echo %%~$PATH:i
goto :eof
)
)
:: note: WHERE lists all occurrences of a file on the PATH in PATH order
goto :eof
Two changes:
References:
–jeroen
Posted in Batch-Files, Development, Power User, Scripting, Software Development, The Old New Thing, Windows, Windows Development | Leave a Comment »
Posted by jpluimers on 2018/11/15
My solution in [WayBack] delphi – post-build event with multiple if/copy combinations only execute if first file does not exist – Stack Overflow is an addendum to my 2014 post Delphi prebuild/prelink/postbuild events.
Here we go:
Posted in Conference Topics, Conferences, Delphi, Development, Event, Software Development, The Old New Thing, Windows Development | Leave a Comment »
Posted by jpluimers on 2018/09/11
On x86/x64/ARM/…:
It’s where the function is going to return to, not where it came from.
And:
Bonus chatter: This reminds me of a quirk of the 6502 processor: When it pushed the return address onto the stack, it actually pushed the return address minus one. This is an artifact of the way the 6502 is implemented, but it results in the nice feature that the stack trace gives you the line number of the call instruction.
Of course, this is all hypothetical, because 6502 debuggers didn’t have fancy features like stack traces or line numbers.
Source: [WayBack] Remember that in a stack trace, the addresses are return addresses, not call addresses – The Old New Thing
Which resulted in these comments at [WayBack] CC +mos6502 – Jeroen Wiert Pluimers – Google+:
- mos6502: And don’t forget the crucial difference in PC on 6502 between RTS and RTI!
- Jeroen Wiert Pluimers: +mos6502 I totally forgot about that one. Thanks for reminding me
<<Note that unlike RTS, the return address on the stack is the actual address rather than the address-1.>>
References:
[WayBack] 6502.org: Tutorials and Aids – RTI
RTI retrieves the Processor Status Word (flags) and the Program Counter from the stack in that order (interrupts push the PC first and then the PSW).
Note that unlike RTS, the return address on the stack is the actual address rather than the address-1.
[WayBack] 6502.org: Tutorials and Aids – RTS
RTS pulls the top two bytes off the stack (low byte first) and transfers program control to that address+1. It is used, as expected, to exit a subroutine invoked via JSR which pushed the address-1.
RTS is frequently used to implement a jump table where addresses-1 are pushed onto the stack and accessed via RTS eg. to access the second of four routines.
–jeroen
Posted in 6502, 6502 Assembly, Assembly Language, Development, History, Software Development, The Old New Thing, Windows Development, x64, x86 | Leave a Comment »
Posted by jpluimers on 2018/08/16
Cool feature borrowed from Notepad, which can read files locked by other references (for instance a process having the handle open): [WayBack] c# – Notepad beats them all? – Stack Overflow.
The example from the answer is in .NET, but can be used in a native environment as well (Notepad is a native application).
Notepad reads files by first mapping them into memory, rather than using the “usual” file reading mechanisms presumably used by the other editors you tried. This method allows reading of files even if they have an exclusive range-based locks.
You can achieve the same in C# with something along the lines of:
using (var f = new FileStream(processIdPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite)) using (var m = MemoryMappedFile.CreateFromFile(f, null, 0, MemoryMappedFileAccess.Read, null, HandleInheritability.None, true)) using (var s = m.CreateViewStream(0, 0, MemoryMappedFileAccess.Read)) using (var r = new StreamReader(s)) { var l = r.ReadToEnd(); Console.WriteLine(l); }
Via: [WayBack] Maintaining Notepad is not a full-time job, but it’s not an empty job either – The Old New Thing
–jeroen
Posted in .NET, Delphi, Development, Software Development, The Old New Thing, Windows Development | Leave a Comment »
The Wiert Corner - irregular stream of stuff 