The Wiert Corner – irregular stream of stuff

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

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Archive for the ‘Delphi’ Category

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Get it at a discount while it is hot: Delphi Thread Safety Patterns eBook by Dalija Prasnikar and Neven Prasnikar Jr.

Posted by jpluimers on 2022/06/01

Get the new [Wayback/Archive] Delphi Thread Safety Patterns eBook at a discount while it is hot:

Use Coupon Code: DTSPATT10 at checkout to get a $10 discount.
This promotional offer is valid through June 14.

Read the rest of this entry »

Posted in Delphi, Development, Encoding, ISO-8859, ISO8859, Mojibake, Multi-Threading / Concurrency, Software Development, UTF-8, Windows-1252 | Leave a Comment »

On Windows, keep the lifetime of relative pathnames as short as possible because of thread-safety issues

Posted by jpluimers on 2022/05/18

Subtitle:

GetFullPathName thread-unsafety because of SetCurrentDirectory isn’t, so derived functions (like Delphi GetDir/ChDir/TPath.GetFullPath, or .NET System.IO.Path.GetFullPath) are not thread-safe either (via The Old New Thing)

A while ago I got a big reminder because of [Wayback] What are these dire multithreading consequences that the GetFullPathName documentation is trying to warn me about? | The Old New Thing:

Read the rest of this entry »

Posted in Delphi, Development, Pascal, Software Development, Turbo Pascal, Windows Development | Leave a Comment »

A while ago @LarsFosdal praised Bruneau Babet for trying to offset the lack of Idera/EMBT customer communication and quality control: Lars Fosdal is right

Posted by jpluimers on 2022/05/17

Earlier this year, [Wayback/Archive] Lars Fosdal posted a long thread about Embarcadero/IDERA software quality and one special person trying to offset the lack.

It is important not just because of his opinion, but also because Lars posts rarely about his Delphi opinion. He is the kind of guy quietly working with Delphi and doing a lot of community support.

When he posts, it is important and should be a signal to be picked up by Embarcadero/IDERA. Until now, not so much of that.

The first tweet was this:

Read the rest of this entry »

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

The Delphi documentation site docwiki.embarcadero.com has been down/up oscillating for 4 days is now down for almost a day.

Posted by jpluimers on 2022/03/08

The [Wayback/Archive] Embarcadero/IDERA Documentation Wiki has been mostly down since March 3rd, 2022 (not the main page, but almost all other pages are).

I modified [Wayback/Archive] Docwiki https – EmbarcaderoMonitoring to show the actual status of a deeper page as the (mostly static) top page is up, so monitoring that is useless as the deeper pages are down.

The deeper pages are dynamic and require a functioning MySQL database connection. That connection is mostly down (the error message is not clear, so this could be a network or a database server problem, or maybe even a loadbalancer gradually entering bit heaven).

Since it had been down for like 6 days in February*, I’d expect Idera to keep an eye on it and prepare for more downtime. Apparently that’s either not a 24×7 thing for them or  they missed the “pre” in preparation as it is dead-silent on .

It also runs on an unsupported version of Mediawiki 1.31** which by itself does not explain the outage, but does indicate that their idea of handling their internal lifetime management is different than what they advocate to clients in their software subscription model, see [Wayback/Archive] Delphi – Embarcadero store, [Wayback/Archive] Update Subscription – Embarcadero and [Wayback/Archive] Special Offers on RAD Studio, Delphi & C++Builder – Embarcadero:

Read the rest of this entry »

Posted in *nix, Bookmarklet, Delphi, Development, JavaScript/ECMAScript, Lightweight markup language, MediaWiki, Monitoring, Power User, Scripting, SocialMedia, Software Development, Twitter, Uptimerobot, Web Browsers | Leave a Comment »

DELPHI : EEncodingError – Invalid code page on windows xp embedded – Stack Overflow

Posted by jpluimers on 2022/02/15

From my Windows XP days  (which are long gone), but historically relevant the answer to [Wayback] DELPHI : EEncodingError – Invalid code page on windows xp embedded – Stack Overflow by [Wayback] Remy Lebeau:

The TEncoding.ASCII property uses codepage 20127, which is not installed on XP Embedded by default. You have to install it manually. The TEncoding class does not exist in D2006.

Are you using Indy 10, by chance? It uses TEncoding.ASCII by default for its string encodings. This exact error has been known to occur when using Indy on XP Embedded.

–jeroen

Posted in ASCII, Delphi, Development, Encoding, Power User, Software Development, XP-embedded | Leave a Comment »

When floating point code suddenly becomes orders magnitudes slower (via C++ – Why does changing 0.1f to 0 slow down performance by 10x? – Stack Overflow)

Posted by jpluimers on 2022/01/26

When working with converging algorithms, sometimes floating code can become very slow. That is: orders of magnitude slower than you would expect.

A very interesting answer to [Wayback] c++ – Why does changing 0.1f to 0 slow down performance by 10x? – Stack Overflow.

I’ve only quoted a few bits, read the full question and answer for more background information.

Welcome to the world of denormalized floating-point! They can wreak havoc on performance!!!

Denormal (or subnormal) numbers are kind of a hack to get some extra values very close to zero out of the floating point representation. Operations on denormalized floating-point can be tens to hundreds of times slower than on normalized floating-point. This is because many processors can’t handle them directly and must trap and resolve them using microcode.

If you print out the numbers after 10,000 iterations, you will see that they have converged to different values depending on whether 0 or 0.1 is used.

Basically, the convergence uses some values closer to zero than a normal floating point representation dan store, so a trick is used called “denormal numbers or denormalized numbers (now often called subnormal numbers)” as described in Denormal number – Wikipedia:

…

In a normal floating-point value, there are no leading zeros in the significand; rather, leading zeros are removed by adjusting the exponent (for example, the number 0.0123 would be written as 1.23 × 10−2). Denormal numbers are numbers where this representation would result in an exponent that is below the smallest representable exponent (the exponent usually having a limited range). Such numbers are represented using leading zeros in the significand.

…

Since a denormal number is a boundary case, many processors do not optimise for this.

–jeroen

Posted in .NET, Algorithms, ARM, Assembly Language, C, C#, C++, Delphi, Development, Software Development, x64, x86 | Leave a Comment »

Some uptime monitoring tools that are still free and understand more than http/https

Posted by jpluimers on 2022/01/19

Since uptimerobot has slowly moving free features, part of my family uses it to monitor uptime of their personal stuff, and I don’t want to pay for the free monitoring I do on Embarcadero infrastructure (I know that they have been phasing out older useful sites for ages, but even their main sites were down for 2 days about a year ago).

Yes, I know the competitiveness of [Wayback] Website monitoring – Wikipedia, and I’m glad Uptimerobot has been there for a relatively long time, but alas: for personal use…

The list of of the pricing pages of each site, containing a one line summary blurb if it was available:

Via [Wayback] 16 Best Online Services to Monitor Sites Uptime

–jeroen

Posted in *nix, Delphi, Development, Monitoring, Power User, Software Development | Leave a Comment »

Delphi SetRoundMode: gets sets part of the 8087 control word (related: GetRoundMode and TFPURoundingMode)

Posted by jpluimers on 2022/01/12

I thought I had written about this a long time ago, as Math.SetRoundMode (and now System.Math.SetRoundMode) has been introduced since at least Delphi 2007. There are also related GetRoundMode and TFPURoundingMode.

Delphi 2009 also introduced TFPUPrecisionMode, GetPrecisionMode and SetPrecisionMode.

Delphi 2010 also introduced TFPUException, TFPUExceptionMask, TFPUPrecisionMode, TFPURoundingMode, ClearExceptions, GetExceptionMask, and SetExceptionMask.

Delphi XE2 introduced namespaces, so prepended the unit Math with the namespace System. to become unit System.Math. It also introduced $EXCESSPRECISION (for x64), GetMXCSR, SetMXCSR, ResetMXCSR, ClearFPUExceptions, TSSEException, TSSEExceptionMask, GetSSEExceptionMask, SetSSEExceptionMask, ClearSSEExceptions, TSSERoundingMode, GetSSERoundMode, SetSSERoundMode.

The documentation basically only had formatting changes. This is the most important part of SetRoundMode:

function SetRoundMode(const RoundMode: TFPURoundingMode): TFPURoundingMode;

…

Call SetRoundingMode to specify how the FPU handles rounding issues. The rounding mode can be any of the following values:

Value
Meaning
rmNearest
Rounds to the closest value.
rmDown
Rounds toward negative infinity.
rmUp
Rounds toward positive infinity.
rmTruncate
Truncates the value, rounding positive numbers down and negative numbers up.

This is the most important bit of SetPrecisionMode:

function SetPrecisionMode(const Precision: TFPUPrecisionMode): TFPUPrecisionMode;

…

Call SetPrecisionMode to specify the level of precision that the FPU (floating-point unit) uses for floating-point calculations. The precision control mode can be any of the following values:

Value
Meaning
pmSingle
single precision
pmReserved
not used
pmDouble
double precision
pmExtended
extended precision

SetPrecisionMode returns the previous precision control mode.

Both are functions, so so they return the previous value which you can use to set it back later: this is important as it is a process wide. SetPrecisionMode documents this, but SetRoundMode does not!

Global side effects and avoiding them

Since SetRoundMode and SetPrecisionMode set the 8087 CW (and on XE2 and up SetMXCSR), it means all usual Set8087CW caveats apply: changing the global 8087 CW setting impacts all running code, which means that threads, DLLs (especially ones written in other languages), etc might malfunction. You can find some of the caveat effects on my bog by searching for [Wayback] Set8087CW site:wiert.me – Google Search.

If you want to avoid global side effects, you might try the solution in [Wayback] c# – What is the equivalent of Math.Round() with MidpointRounding.AwayFromZero in Delphi? – Stack Overflow by [Wayback] Andreas Rejbrand.

On MXCSR

[Wayback/Archive.is] SSE Instruction Set (not sure why Embarcadero used this as reference material from their docwiki, but hey, Intel documentation is likely outdated):

SSE — MXCSR

The MXCSR register is a 32-bit register containing flags for control and status information regarding SSE instructions. As of SSE3, only bits 0-15 have been defined.

Pnemonic Bit Location Description
FZ bit 15 Flush To Zero
R+ bit 14 Round Positive
R- bit 13 Round Negative
RZ bits 13 and 14 Round To Zero
RN bits 13 and 14 are 0 Round To Nearest
PM bit 12 Precision Mask
UM bit 11 Underflow Mask
OM bit 10 Overflow Mask
ZM bit 9 Divide By Zero Mask
DM bit 8 Denormal Mask
IM bit 7 Invalid Operation Mask
DAZ bit 6 Denormals Are Zero
PE bit 5 Precision Flag
UE bit 4 Underflow Flag
OE bit 3 Overflow Flag
ZE bit 2 Divide By Zero Flag
DE bit 1 Denormal Flag
IE bit 0 Invalid Operation Flag

FZ mode causes all underflowing operations to simply go to zero. This saves some processing time, but loses precision.

The R+, R-, RN, and RZ rounding modes determine how the lowest bit is generated. Normally, RN is used.

PM, UM, MM, ZM, DM, and IM are masks that tell the processor to ignore the exceptions that happen, if they do. This keeps the program from having to deal with problems, but might cause invalid results.

DAZ tells the CPU to force all Denormals to zero. A Denormal is a number that is so small that FPU can’t renormalize it due to limited exponent ranges. They’re just like normal numbers, but they take considerably longer to process. Note that not all processors support DAZ.

PE, UE, ME, ZE, DE, and IE are the exception flags that are set if they happen, and aren’t unmasked. Programs can check these to see if something interesting happened. These bits are “sticky”, which means that once they’re set, they stay set forever until the program clears them. This means that the indicated exception could have happened several operations ago, but nobody bothered to clear it.

DAZ wasn’t available in the first version of SSE. Since setting a reserved bit in MXCSR causes a general protection fault, we need to be able to check the availability of this feature without causing problems. To do this, one needs to set up a 512-byte area of memory to save the SSE state to, using fxsave, and then one needs to inspect bytes 28 through 31 for the MXCSR_MASK value. If bit 6 is set, DAZ is supported, otherwise, it isn’t.

Architectures Software Developer’s Manual: Intel® 64 and IA-32 includes supporting processors programming environment and architecture.

[Wayback] Intel® 64 and IA-32 Architectures Developer’s Manual: Vol. 1

[Wayback]

https://web.archive.org/web/20130603170547/http://www.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-software-developer-vol-1-manual.pdf

Documentation links

Some of the documentation links (that regrettably do not explain what happens behind the scenes with the 8087 CW) are these:

 

–jeroen

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

When MySQL characterset ‘utf’ does not allow you to enter some Unicode code points

Posted by jpluimers on 2022/01/06

Contrary to what many believe is that MySQL utf8 is not always full blown UTF-8 support, but actually utf8mb3, which has been deprecated for a while now.

Only utf8mb4 will give you full blown UTF-8 support.

This when someone reminded me of this in a Delphi application:

When I insert :joy: emoji into mysql varchar filed I got an error :
#22007 Incorrect string value: '\xF0\x9F\x98\x82' for column 'remarks' at row 1

database charset is utf8

Note that the :joy: emoji is 😂 and has Unicode code point U+1F602 which is outside the basic multilingual plane.

See:

–jeroen

Posted in Conference Topics, Conferences, Database Development, Delphi, Development, Encoding, Event, MySQL, Software Development, UTF-8, UTF8 | Leave a Comment »

Delphi design-time packages: “%1 is not a valid Win32 application”

Posted by jpluimers on 2021/12/22

For my link archive, as I hardly see this (it happens in many Delphi versions and always has to do with missing/wrong DLLs), so always forget how to solve it.

Basically it is the same fix as for Fixing hg.exe “ImportError: DLL load failed: %1 is not a valid Win32 application.”:

If you get the below error when running hg.exe, then you are mixing a 64-bit Mercurial with 32-bit dependencies.

[Wayback] XE2 – “%1 is not a valid Win32 application” when installing a package – embarcadero.delphi.ide with entries by [Wayback] Remy Lebeau and [Wayback] Jeff Overcash:

I don't know what I did, but when trying to install a set of freshly built 
Delphi Win32 packages into the IDE, XE2 is giving me this error message now:

{quote}
Can't load package ...
%1 is not a valid Win32 application.
{quote}

a

> Often that is caused by the same named 32 and 64 bit run time packages
> and the OS finding the 64 bit first when the IDE must load the 32 bit.  If
> that is the case check your path variable and make sure the 32 bit paths
> appear first.

That was the problem.  The Windows PATH variable had a 64-bit folder in front 
of the 32-bit folder.  Deleted the 64-bit files and the error went away. 
 Noe I'm getting a new error:

{quote}
The program can't start because <RuntimePackage>.bpl is missing from
your computer. Try reinstalling the program to fix this problem.
{quote}

But the "missing" package is in the same folder as the design-time package 
I am trying to install.
Since the design time location is known it is explicitely 
loaded, but the run time is implicitly loaded and follows the dll loading rules. 
  Both are dynamically loaded.

The reason you only see this the next time you restart the IDE is because the 
working directory changes to your project directory when you load a project so 
if the runtime is there it is found that way, but the next time you load the IDE 
the working directory starts in the bin directory.
I thought it was, but turns out the 32-bit output folder had been moved and 
the PATH was not updated accordingly.  Fixed the PATH and now the packages 
install.

–jeroen

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

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