The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

  • My badges

    Mastodon

  • Twitter Updates

  • My Flickr Stream

    20140508-Delphi-2007--Project-Options--Cannot-Edit-Application-Title-HelpFile-Icon-Theming20140430-Fiddler-Filter-Actions-Button-Run-Filterset-now20140424-VMware-Fusion-6.0.3.-no-reclaimable
    More Photos

  • Pages

  • All categories

  • Enter your email address to subscribe to this blog and receive notifications of new posts by email.

    Join 1,860 other subscribers

Archive for the ‘C++’ Category

« Previous Entries
Next Entries »

A garbage collector for C and C++ (and a wrapper for Delphi): The Boehm-Demers-Weiser conservative C/C++ Garbage Collector

Posted by jpluimers on 2020/12/30

I bumped into [WayBack] A garbage collector for C and C++ a while ago, for which the source is at [WayBack] GitHub – ivmai/bdwgc: The Boehm-Demers-Weiser conservative C/C++ Garbage Collector (libgc, bdwgc, boehm-gc).

There is a (very old!) wrapper for Delphi too: [WayBack] 21646 API for Boehm Garbage Collector DLL

Barry Kelly <barry_j_kelly@hotmail.com>,
19 April 2004
——————————————————
This archive contains a simple API unit for the Boehm Garbage Collector DLL, along with another unit which makes it easier to use with classes, and a demonstration application. Also included is the Boehm GC DLL binary, along with source code in the gc_dll_src directory.

The files:

BoehmGc.pas
———–
This unit exports a dozen or so routines from the Boehm GC dll. Since the GC integrates with and replaces the Delphi default memory manager, you probably don’t need to use this unit unless you want to fine-tune the behaviour of the DLL. The DLL exports more routines than are in this unit; the C prototypes are in the gc_dll_src/gc.h header file, and can be imported as needed. If you allocate large chunks of memory (>100K) which don’t contain references to other chunks (and thus don’t need to be scanned for pointers), there are routines in this unit which you can use to increase performance.

General advice: don’t tweak until you need to tweak.

Gc.pas
——
This is the main unit. Put this unit first in the uses clause of you project and the project will automatically use garbage collection. If you want to use objects which require finalization and you don’t want to have to call TObject.Free / TObject.Destroy on them manually, you can use the MarkForFinalization(TObject) function. The basic pattern is to register the object for finalization in its constructor and unregister it with UnmarkForFinalization in its destructor. This handles the two most common use cases for finalization: GC-invoked finalization and manual finalization. Note that it’s always safe to behave as if GC doesn’t exist, and use GetMem/FreeMem, New/Dispose, Create/Free etc. The use of these units simply allows you to also program with garbage collection.

GcTest.dpr & GcTest.exe
———————–
This program contains simple sample code demonstrating the garbage collector in action.

BoehmGC.dll
———–
This contains the implementation of the garbage collector itself. The DLL can be recompiled from the source in gc_dll_src with various options, including multithreaded support, different pointer alignment granularities, etc.

****
The original Boehm GC source comes from: http://www.hpl.hp.com/personal/Hans_Boehm/gc/

I’m Barry Kelly: barry_j_kelly@hotmail.com

You can do anything you like with my source code (*.pas, *.dpr).

See the file gc_dll_src/LICENSEa for permissions for the GC itself.

</barry_j_kelly@hotmail.com>

Although when trying to download, I got this for both cc.embarcadero.com/Download.aspx?id=21646 and cc.embarcadero.com/Download.aspx?id=21646&prot=ftp:

Access to the path ‘\\etnaedndb02.embarcadero.com\f\webcache\cc\2004\4\19\21646.zip’ is denied.

An error has occurred while processing the page.

Please try to refresh the page, or return to the home page.

: ETNACDC04

and [WayBack] Jeroen Pluimers auf Twitter: “It looks like the @EmbarcaderoTech code central file cc.embarcadero.com/Item/21646 is broken: “Access to the path ‘\https://t.co/3f3blXN9mp\f\webcache\cc\2004\4\19\https://t.co/0UJUtWvxVV’ is denied.” when exploring or downloading.…”

 Explore the files in this upload

File Exploration is Disabled

We’re sorry, but errors in the uploaded zip file prevent it from being explored.

The error generated by the Zip attachment is:

Access to the path ‘\\etnaedndb02.embarcadero.com\f\webcache\cc\2004\4\19\21646.zip’ is denied.You may still be able to repair the zip file contents if you download the entire zip locally. You may also want to ask the author to repost the attachment.

Via [WayBack] delphi – Reference-counting for objects – Stack Overflow which also points to:

Downloads of stable versions: [WayBack] Download · ivmai/bdwgc Wiki · GitHub

–jeroen

Read the rest of this entry »

Posted in C, C++, Delphi, Development, Software Development | Leave a Comment »

List Of Windows Messages – WineHQ Wiki

Posted by jpluimers on 2020/12/17

Easiest way to find which message # (decimal or hexadecimal) belongs to which message and vice versa:

None of the lists are completely accurate, but they get you going.

For comparison: an early Windows 10 SDK WinUser.h and [Archive.is] NativeMethods.cs

Translations:

–jeroen

Posted in C, C++, Delphi, Development, Software Development | Leave a Comment »

Fl Ko: Getting the pixel position of the current editor cursor position for an OTA wizard

Posted by jpluimers on 2020/09/08

Since WayBack cannot save G+ photos, here is one from [WayBack] So, now I’m in front of a problem similar to a former one: I need to get the pixel position of the current editor cursor position for my OTA wizard. I’… – Fl Ko – Google+:

Related:

–jeroen

Posted in C++, C++ Builder, Delphi, Development, Software Development | Leave a Comment »

A Tale of Many Divisions – Naive Prime Factorization Across a Handful of Architectures

Posted by jpluimers on 2020/06/16

[WayBack] A Tale of Many Divisions – Naive Prime Factorization Across a Handful of Architectures

Source code: [WayBack] GitHub – blu/euclid: An extremely naive prime factorizer

Via: [WayBack] Blu looks at how a small piece of code with divisions surprisingly behave on various architecture: #Arm, #MIPS, and #x86. – Jean-Luc Aufranc – Google+

–jeroen

Posted in Assembly Language, C++, Development, Software Development | Leave a Comment »

The Invention of C++ – Nice bit of net lore

Posted by jpluimers on 2020/04/30

This is a nice joke: [WayBack] The Invention of C++ – Nice bit of net lore.

But the actual interview linked from the article is quite nice: [WayBack: The Real Stroustrup Interview]

By the name, I found the actual (hopefully still online when this gets out of the blog post queue) version at [WayBack] Stroustrup: Interviews under [WayBack] stroustrup.com/ieee_interview.pdf

–jeroen

Via: [WayBack] The invention of C++ – Thomas Mueller (dummzeuch) – Google+

Posted in C, C++, Development, History, Software Development | Leave a Comment »

OMF, COFF and the 32-bit/64-bit Delphi or C++ compilers

Posted by jpluimers on 2020/01/29

Via [WayBack] As far as I can tell (and documentation on that is reaaaaaaly hard to find), dcc64 can link in .obj files in OMF and COFF format. Bcc64 uses LLVM chain and therefore produces ELF .o files… – Primož Gabrijelčič – Google+:

David Heffernan:
dcc32 does coff and omf, dcc64 only coff

and later he commented:

One of the difficulties with linking objects is the handling of exceptions. The 64 bit exception model is table based, in contrast to the stack based 32 bit model.

I don’t think that the exception tables are written correctly for code linked in objects. If exceptions are raised then this can lead to abnormal process termination. Process just disappears. Poof!

One common way that this happens is floating point exceptions that are by default unmasked by the Delphi RTL. I have found it necessary to mask them when calling into any linked object code to avoid exceptions being raised.

And compiling with cl can be a bit of a game. It’s stack checking options need to be disabled. And there are a few other key switches that help. And then there’s the forward declaration trick to help the one pass compiler cope with C objects that are expected to be linked in a separate step.

Anyway, it can be quite a challenge at times, but I’ve yet to find a plain self contained C library that has defeated me!

–jeroen

Posted in C++, C++ Builder, Delphi, Delphi x64, Development, Software Development, Visual Studio C++ | 2 Comments »

Flexible and Economical UTF-8 Decoder

Posted by jpluimers on 2019/12/25

For my link archive: [Archive.is] Flexible and Economical UTF-8 Decoder.

Be sure to read the whole article there as the explanation of the initial algorithm is important and final algorithm is towards the end.

The foundation is a state machine combined with a lookup table to find the initial state and proceed to subsequent states.

Related (and reminder to check what David did):

–jeroen

Read the rest of this entry »

Posted in C, C++, Delphi, Development, Software Development | 1 Comment »

Teach Yourself C++ in 21 days…

Posted by jpluimers on 2019/10/10

[WayBack] Abtruse Goose: Teach Yourself C++ in 21 days…

Via: [WayBack] “How to learn programming in 21 Days” – CodeProject – Google+

Read the rest of this entry »

Posted in C, C++, Development, Fun, Software Development | Leave a Comment »

Design Patterns & Refactoring

Posted by jpluimers on 2019/07/16

Design Patterns and Refactoring articles and guides. Design Patterns video tutorials for newbies. Simple descriptions and full source code examples in Java, C++, C#, PHP and Delphi.

Source: [WayBack] Design Patterns & Refactoring.

And indeed a lot of examples in Delphi too; few sites have that: Delphi site:sourcemaking.com.

–jeroen

Via: [WayBack] I stumbled upon this yesterday, very informative, accessible and also with Delphi examples – among other languages. – Steffen Nyeland – Google+

Posted in .NET, C, C#, C++, Delphi, Design Patterns, Development, Java, Java Platform, PHP, Scripting, Software Development | Leave a Comment »

It was all Greek to me: Iota · golang/go

Posted by jpluimers on 2019/05/21

Context is king!

Being Dutch, my association with iota was the phrase “Ik snap er geen iota van” (English: “It’s all Greek to me”), basically indicating iota is extremely small, similar to [WayBack] Iota | Definition of Iota by Merriam-Webster:

1: an infinitesimal amount : jot  (did not show an iota of interest)
2: the 9th letter of the Greek alphabet — see alphabet table

But the first time, I saw iota used in golang, I actually confused it with [WayBack] itoa – C++ Reference, because I am more than slightly wordblind.

So code like this was all Greek to me at first, not understanding the conversion from integer to ASCII**, and slightly later, not understanding iota to be extremely small either. Heck, its usage indicates it is small from infinitesimal:

const (
    _           = iota // ignore first value by assigning to blank identifier
    KB ByteSize = 1 << (10 * iota)
    MB
    GB
    TB
    PB
    EB
    ZB
    YB
)

So it took me a bit of thought to realise that it actually had to mean something completely different, so I found

It makes me wonder why they named it like this.

Slightly related:

–jeroen

Read the rest of this entry »

Posted in C++, Development, Go (golang), Software Development | Leave a Comment »

« Previous Entries
Next Entries »