Preprocessor regression in MT5's build 3950 is not a "beta" - General

Fernando Carreiro 2023.09.18 20:06 #21

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yoriz, 2023.09.18 21:07

There appears to be a regression in build 3950 (14 Sep 2023) in the behavior of the preprocessor. The code below compiles without errors on the old build 3802 (9 Jun 2023):

#define NAME(prefix, linenr)     prefix##linenr
#define MAKE_VAR \
   int NAME(example, __LINE__) = 123

void OnStart() {
   MAKE_VAR; // int example6 = 123;
   MAKE_VAR; // int example7 = 123;
}

However, when compiling this same code in build 3950, I get an error message:

'example__LINE__' - variable already defined
see declaration of variable '"void OnStart()"::example__LINE__'

Unfortunately, I use preprocessor concatenation ## a lot in my code so all my experts and indicators are now broken and don't compile anymore...

I filed a bug report here: https://www.mql5.com/en/forum/628/page112#comment_49409863 (because Service Desk chat-bot did not understand me and was not filing a bug)

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yoriz 2023.09.19 17:10 #22

Dominik Egert #:

Dont feel so pesimistic, its still beta, and probably just an unfixed bug.

How can you say that?! They force everybody to upgrade. That is not a "beta"! That is breaking all MT5's world-wide.

MetaQuotes needs to hire a professional software QA specialist. Who knows how to properly set up CI/CD pipelines, regression tests with sufficient coverage, a *voluntary* beta-test program that is not immediately pushed to all users, etc. etc.

I understand MetaQuotes does not want to maintain many different versions, so they want all users on the same version. However, they could consider having an option to downgrade to the previous version if there are bugs found by the community. If no bugs found during a month, then make the version mandatory and disable downgrade.

Alternatively, consider having a single "Long Term Support (LTS)" version that remains untouched for a year or so. After a year, use a more recent version that has been field tested for a few months as the next LTS version, etc.

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yoriz 2023.09.19 17:15 #23

fxsaber #:
Temporary solution.

#define ID(x) x##4##CC91BD6

Unfortunately not working for my case where I concatenate __LINE__:

#define NAME(prefix, linenr) prefix##linenr
#define MAKE_VAR \
int NAME(example, __LINE__) = 123

Any ideas how I can generate different variable names calling the same macro? Doesn't need to be line number so can be something else, but X+1 or X++ does not work in preprocessor of course...

P.S. __COUNTER__ is also not working. Same problem with ## operator.

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Alain Verleyen 2023.09.19 17:58 #24

yoriz #:

Unfortunately not working for my case where I concatenate __LINE__:

#define NAME(prefix, linenr) prefix##linenr
#define MAKE_VAR \
int NAME(example, __LINE__) = 123

Any ideas how I can generate different variable names calling the same macro? Doesn't need to be line number so can be something else, but X+1 or X++ does not work in preprocessor of course...

P.S. __COUNTER__ is also not working. Same problem with ## operator.

MetaQuotes is already aware about these issues. Hopefully they will fix them.

Dominik Egert 2023.09.19 18:35 #25

yoriz #:

How can you say that?! They force everybody to upgrade. That is not a "beta"! That is breaking all MT5's world-wide.

MetaQuotes needs to hire a professional software QA specialist. Who knows how to properly set up CI/CD pipelines, regression tests with sufficient coverage, a *voluntary* beta-test program that is not immediately pushed to all users, etc. etc.

I understand MetaQuotes does not want to maintain many different versions, so they want all users on the same version. However, they could consider having an option to downgrade to the previous version if there are bugs found by the community. If no bugs found during a month, then make the version mandatory and disable downgrade.

Alternatively, consider having a single "Long Term Support (LTS)" version that remains untouched for a year or so. After a year, use a more recent version that has been field tested for a few months as the next LTS version, etc.

At the time I posted, it was still beta.

I agree, life cycle Management is not the best for such a crucial software base. But other companies have similar issues.... MQ doesn't stand out in any direction, neither bad, nor good in this regard.

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Fernando Carreiro 2023.09.20 22:47 #26

Before this latest update I could define function-like macros as follows, without issue ...

#define PositionMagicNumber() PositionGetInteger(  POSITION_MAGIC )

With this new build, this throws an error ...

too many arguments for function-like macro 'PositionMagicNumber'

To resolve it, I have to define it differently, by giving it a parameter, for example as follows ...

#define PositionMagicNumber(_)  PositionGetInteger(  POSITION_MAGIC )

This seems to contradict the way a function-like macro can be defined with an empty parameter list in C/C++. For example, the following can be found in many renditions of the standard C library stdio.h ...

#define getchar( ) getc(stdin)

fxsaber 2023.09.21 05:24 #27

yoriz #:

Any ideas how I can generate different variable names calling the same macro?

Unfortunately, this is not possible now.

fxsaber 2023.09.21 05:28 #28

Fernando Carreiro #:

Before this latest update I could define function-like macros as follows, without issue ...

Trouble with macros is not good. Why don't you use functions in this case?

long PositionMagicNumber() { return(PositionGetInteger(  POSITION_MAGIC )); }

Fernando Carreiro 2023.09.21 13:50 #29

fxsaber #: Trouble with macros is not good. Why don't you use functions in this case?

That was not the point of my post. My point was about the declaration of a function-like macros with an empty parameter list.

AliceRioBR 2023.09.22 01:16 #30

OMG...

I received now the latest non-Beta build 3980.

The STRATEGY TESTER panel is crazy

The "START" button disappeared;
The panel cannot be resized. The mouse is ineffective when we put it in the panel border.

But when we detach the panel, the START button suddenly appears.

It's really annoying that all releases bring bugs together.

(I work in a software development company)

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