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Posts posted by David Heffernan
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1 hour ago, Benmik said:I like that. Yes, it was meant as a rather bitter comment. Dear David: Oh, what a noble mind is here o'erthrown!
Interesting contribution. Thanks.
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22 minutes ago, Mahdi Safsafi said:You shipped a test for comparison !
He means that the difference in performance is so small as to be unimportant to him
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1 hour ago, Mahdi Safsafi said:He showed a disrespect for me
I didn't mean to show you any disrespect. I'm sorry that it came across that way.
All I meant was that I thought the argument that compilation speed was important was bogus. I really did not mean to upset you. I try hard never to make anything I write personal. To me it's always about the technical details.
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4 minutes ago, Kas Ob. said:And i might here add as suggestion to him and few others: to refrain from using the straw man fallacy https://en.wikipedia.org/wiki/Straw_man , many developer in this forum are using this broken logic repeatedly, we are not in enemy or in a contest for likes, right ?
Please show respect, all in all there is no reason go after a person himself (by offending or disrespect) because you think he is wrong, even if he is wrong.
I don't think that anybody here has used a straw man.
And only two people have made any statements directed at an individual, rather than concentrating on the arguments.
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57 minutes ago, Mahdi Safsafi said:I said that any developer should avoid using typed-ordinal-type-constants(Byte, Integer, ...) as this will impact optimization and adds an extra overhead at the compilation-time
Compilation time is not a valid reason to make that choice. I stand by that. Your own measurements backed up my point of view.
58 minutes ago, Mahdi Safsafi said:Yet he said that the test isn't a real-world test
It wasn't.
58 minutes ago, Mahdi Safsafi said:explaining why it's hard to an x64-toolchain to outperform an x86-toolchain
I understand that, but there's no good reason why they shouldn't have the same relative characteristics. So whilst the x64 compiler may well be slower than x86, the x64 compiler should not blow up when presented with huge numbers of typed constants, in a way that the x86 compiler does not.
59 minutes ago, Mahdi Safsafi said:I said that the reason behind why Delphi's compiler not allowing using complex-type constants (e.g: array, record) as true constants was compile time speed
A more plausible explanation to me is simply the history of writeable typed constants.
At this point we all know what each other thinks, and there's little point repeating ourselves any more.
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The biggest issue with constants in Delphi are that typed constants can't be used in certain settings which require true constants to be used. The ones that come to mind are:
1. When declaring typed constants.
2. When declaring attributes.
The inability to used typed constants in these settings is clear weakness in the language.
There are probably more issues, but these are the ones that bite me.
I'm tired of hearing justification for these limitations based on the current implementation. All this talk about single pass, interface vs implementation, writeable typed constants, etc. If the implementation limits you, change it.
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1 hour ago, Kas Ob. said:David, no one suspect that you have more knowledge than many ( may be all) us here in many fields, though you can't be knowing everything all the time in every detail, so please prove you point or drop it, don't steer the subject left and right.
And saying "i was wrong" will not make you lesser person or developer, on contrary you will gain more respect instead of losing some by offending person in person without proof, just using you reputation not your knowledge.
A few milliseconds during a typical compilation is insignificant. That's my opinion. Others may have a different opinion. They are welcome to it.
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38 minutes ago, Kas Ob. said:Can you accept this as example ?
Now you are talking about the generated code. Which is a different issue. Hitherto there has been a long, and in my view bogus, discussion about compilation speed. The OP said that compilation speed was a reason to prefer avoiding typed constants.
The point that I made which seems to have generated such noise is merely that speed of compilation is no reason to prefer true constants over typed constants.
EDIT: I didn't read closely enough. You are claiming that the compile time must be longer because more instructions are emitted? Wow, that's weird. Known to be false also. Consider optimisation. Often this results in fewer instructions emitted, post optimisation. But optimisation is an additional step that can increase compile time
There are good reasons to prefer true constants over typed constants. Compilation speed isn't one of them. Efficiency of generated code is one.
Frankly I'm ambivalent about what you both think. If you want to change the way you code to save a couple of milliseconds of each compilation, then do it. It doesn't bother me.
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4 hours ago, Mahdi Safsafi said:The code showed clearly that they do on x64!!!
Only for a totally unrepresentative example, and only because of implementation defects in that compiler. Not because there is anything conceptual.
Feel free to choose between true and typed constants because of a few milliseconds difference in compilation time. If that means something to you, great. Knock yourself out. For me I will stick to what results in readable and maintainable code, and code that runs most efficiently.
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41 minutes ago, Mahdi Safsafi said:Your point was that typed-constants have no impact on compilation time (you were strongly believing on that, called my explanation BS and asked for tests) !
And your code showed that they don't.
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26 minutes ago, Mahdi Safsafi said:Now, if you still insist, than you should really start giving me a good explanation -as I did- (forget about good explanation, just give an explanation or even come up with just a theory) why a typed-constant does not add any extra overhead on the compiler/linker ?
My point is that the difference in compilation time is insignificant, and absolutely should not drive your choices of how to write the code.
11 minutes ago, Mahdi Safsafi said:When you use many dll(s) ... did you notice that the startup of your app has significantly taking additional time ??? that's because the dynamic-linker (a component from the os-loader) is fixing your symbols !
Certainly for the DLL that I ship, that's not the case. The time spent fixing up symbols isn't great because there aren't that many.
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5 hours ago, Mike Torrettinni said:For integers I have no problem with non-type constant, while for colors (hex numbers)
Colours aren't hex. Hex is just a different way to write an integer, using base 16.
For instance $10=16.
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That's clearly a deficiency in the x64 compiler implementation since the x86 compiler doesn't suffer the problem. The x86 compiler demonstrates that the difference in performance is not due to a fundamental conceptual hurdle, but a poor implementation. We know that the x64 compiler performs very poorly.
In any case the test is totally unrealistic. You aren't going to encounter this in real world code.
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2 minutes ago, Mahdi Safsafi said:That's prove the lack of your experience toward manual compilation/linking and absolutely you have no idea about how a linker work
Show me some evidence based on measurements.
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25 minutes ago, Mahdi Safsafi said:Can you give a good example on when using an ordinal-typed-constant is better than just a constant
As I said, when I need to take the address. An example from my code base is when calling external code, written in Fortran, that expects values to be passed by reference always.
26 minutes ago, Mahdi Safsafi said:You don't need to measure the elapsed time
You do. If you can't provide a real world example where compilation time is significantly impacted, then I call BS.
27 minutes ago, Mahdi Safsafi said:I gave the example just to show you that the reason behind not allowing a true constant for array, record, ... wasn't about the complexity of the type (they can do it at any time ... but they didn't ! not because the type is complex ... after all it's statically initialized ! if the compiler evaluated it ... it can handle it !!!!!!!). Are you convinced ?
I'm talking about the language as it stands today. Your original post was too.
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1 hour ago, Mahdi Safsafi said:If you need to get an address of a constant, you should probably make it a variable
The fact that you've never come across a need for taking the address of a constant doesn't mean the need doesn't exist.
How about asking why this need arises rather than thinking you've seen all possible use cases for typed constants.
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1 hour ago, Mahdi Safsafi said:If compiler treats typed-constant as constant it will be a factor and I clearly explained that !
I didn't see the part where you measured compile times.
1 hour ago, Mahdi Safsafi said:That's not true!
It is true. We're talking about Delphi. We're not talking about some potential other language.
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Conclusions seem bogus to me. I don't think the compilation speed is a factor, and there are plenty of times when you use typed constants for integers.
The rules really should be:
1. Use true constants if possible.
2. Otherwise use a typed constant.
The factors that force you to use typed constants are broadly because the type is a complex type which doesn't permit true constants. Or you need to take the address of the constant.
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Wait a minute. If its a 64 bit add in then why are you casting the pointer to a 32 bit integer?
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I highly doubt that wordID or hdl are really THandle. The latter should be HWND. Not sure what the former should be. THandle represents a kernel handle. It's something that you would call CloseHandle on.
As for your problem, hard to know. Could be UIPI. You don't do any error checking when you call SendMessage. You need to add some trace debugging.
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1 hour ago, Lars Fosdal said:qp is down again 😕
Couldn't take the traffic of tens of devs trying to vote for range checking enabled by default
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1 hour ago, Kas Ob. said:You both didn't answer my simple short questions, you are steering this away, and lets stay to single subject point, does the Delphi compiler have consistent logical behavior.
Let's start by establishing whether or not there is a problem that cannot be worked around.
Which integer value are you unable to declare as a literal?
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I have a question for you.
Which integer value are you unable to declare as a literal?
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23 minutes ago, Leif Uneus said:The type is still extended, but the value will be as a single(0.1)
It's more nuanced. Assign it to a single variable, and it's just a 4 byte assignment. At least that's how it always has been for floating point literals. Its type is only really crystallised then you assign it is how you might think about it.
Typed constants in Delphi.
in RTL and Delphi Object Pascal
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This is what you mean by friendliness, respect, tact is it? Perhaps I'm missing the point.