Where does this state that it is kernel32.dll?

[T]

Hi All,

Windows

I know from other sources that this call is to a function
in Kernel32.dll.

https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/ns-sysinfoapi-memorystatusex

But where on the page does it state such (kernel32.dll)?
Am I going blind?

Many thanks,
-T

[R.Wieser]

T,

Post by T
But where on the page does it state such (kernel32.dll)?

It doesn't. You can even search for that 'sysinfoapi.h' file and get
nowhere either.

Post by T
Am I going blind?

Nope.

As far as MS is concerned, you do not need to know "trivial" low-level stuff
like that. Just install their latest compiler and it will figure out for
you where all that stuff should be coming from.

And I wish you luck when you go look for (argument) constants : the names
and their purposes will be in a table, but you will need to grab their
actual values from somewhere else.

(I run in it all the time, as I'm an Assembly programmer.)


Want an example of their baddness ? Here :

https://docs.microsoft.com/en-us/windows/win32/api/shlwapi/ne-shlwapi-filetypeattributeflags

That list is not actually a enumeration but instead bitflags (0x1, 0x2, 0x4,
0x8, 0x10, etc.) *and* it misses some entries - which means that even if
you know that those constants are bitflags *and* realize that the
'"FTA_None" will most likely have the value 0x0 (I missed that the first
time around :-| ) you will get the wrong values for the constants later in
the list. Like FTA_NoRecentDocs looks, from that list, to have the value
0x00020000, where it actually has the value 0x00100000 (entries for
0x00004000, 0x00040000 and 0x00080000 are missing).

You may guess three times how I know the above, and the first two don't
count. :-)

tl;dr:
Become accustomed with being disappointed by the ammount of actual
information an MSDN page provides.

Regards,
Rudy Wieser

[T]

Post by R.Wieser
T,

Post by T
But where on the page does it state such (kernel32.dll)?

It doesn't. You can even search for that 'sysinfoapi.h' file and get
nowhere either.

Post by T
Am I going blind?

Nope.
As far as MS is concerned, you do not need to know "trivial" low-level stuff
like that. Just install their latest compiler and it will figure out for
you where all that stuff should be coming from.
And I wish you luck when you go look for (argument) constants : the names
and their purposes will be in a table, but you will need to grab their
actual values from somewhere else.
(I run in it all the time, as I'm an Assembly programmer.)
https://docs.microsoft.com/en-us/windows/win32/api/shlwapi/ne-shlwapi-filetypeattributeflags
That list is not actually a enumeration but instead bitflags (0x1, 0x2, 0x4,
0x8, 0x10, etc.) *and* it misses some entries - which means that even if
you know that those constants are bitflags *and* realize that the
'"FTA_None" will most likely have the value 0x0 (I missed that the first
time around :-| ) you will get the wrong values for the constants later in
the list. Like FTA_NoRecentDocs looks, from that list, to have the value
0x00020000, where it actually has the value 0x00100000 (entries for
0x00004000, 0x00040000 and 0x00080000 are missing).
You may guess three times how I know the above, and the first two don't
count. :-)
Become accustomed with being disappointed by the ammount of actual
information an MSDN page provides.
Regards,
Rudy Wieser

Hi Rudy,

I was not actually trying to use the function. I am trying
to understand the following tutorial:

https://raku-advent.blog/2020/12/09/day-11-getting-windows-memory-usage-with-nativecall/

And where they got "kernel32" from in the following line:

sub GlobalMemoryStatusEx(MEMORYSTATUSEX) is native('Kernel32') returns
int32 { * };

My goal is to under stand methods, classes, and objects in
Raku. And the Raku documentation is terrible:

https://docs.raku.org/language/classtut

And they have the balls to call the page:

"A tutorial about creating and using classes in Raku"

When they refuse to define any of their terms starting
with "what is a 'class'?". You are left to guest from
context

I complain a lot of about the sorry state of their
documentation. Their response on this page was that
I should already understand that this is Object Oriented
programming. In other words, if I knew what was going
on, I would not need their s***ty tutorial.

So I am trying to write up one for myself. I did
find this in Perl 5, which ACTUALLY defines what
things are:

https://perldoc.perl.org/perlglossary#class
https://perldoc.perl.org/perlglossary#object

So a "class" is a declaration of a custom structure of
a collection of variables. The name "class" is
pulled out of someone's ear and you just have to
live with the obscure meaning they have attached to it.

And an "object" is when you declare a structure
using a "class". Object is a little less obscure.
It is better that "a variable of variables".

And I am still working on a "method" definition,
and where they fit into the classes declaration,
although I use methods extensively

say (-5..5).rand.truncate.abs**3
64

Which means to picks out a random number between -5
and 5, truncate it into and integer, turn it
into a positive number, then cube it. Rand,
truncate, and abs are all methods.

They can be fun little buggers!

Thank you for the assist!

-T

[R.Wieser]

T,

First things first: while my complaint about MSDN information still stands,
I made a mistake when looking at the link you provided : I fully missed it
described a structure, not a function (as Kaz made clear). There is some
logic to only have it refer to its "parent", the function, just as the
function refers to its "parent", the DLL.

Post by T
sub GlobalMemoryStatusEx(MEMORYSTATUSEX) is native('Kernel32') returns
int32 { * };

You're asking where /they/ got their information from ? Thats impossible
to say ...

But, if you just want to know which DLL contains a certain function name,
than, apart from googeling for it, you could extract the function names from
all the Windows DLLs[1] and put them into lists for easy searching.

[1] which, alas, most of them do *not* contain any information about the
ammount and types of their arguments.

Post by T
"A tutorial about creating and using classes in Raku"

Hmmm... I can read that line as "you already know what a class is, here we
describe how you use them in the Raku language".

As far as I can tell there is not much you can know about a class : its a
container for methods (functions) and properties (variables), and you can
create multiple instances from a single template[2]. The rest
(implementation) is language dependant.

[2] In that regard its properties work the same as a function with local
variables : each has and manages its own variables (properties). You can
call such a function multiple times withouth having them mix up their local
variables.

Post by T
When they refuse to define any of their terms starting
with "what is a 'class'?". You are left to guest from
context

While you are right, think about it : how deep do they need to go ? At
some point they would end up telling you about the best places to delve
silica sand to create the wavers from from which the chips are created that
make your computer work. Also, what is commonly referred to as "electrical
current" does not actually exist. Electrons flow from the negative terminal
towards the postive one, not the other way around. :-)

But granted, I would have been nice of them to mention which knowledge they
expect you to already have (so you can go google for it beforehand).

Post by T
I did find this in Perl 5, which ACTUALLY defines what
https://perldoc.perl.org/perlglossary#class

I disagree that that is a good description. They could as well have said
"see 'data type' "and be done with it.

Also, a class doesn't need to be "set of possible values, together with all
the operations that know how to deal with those values". Take for instance
a class which does a ROT16 operation. It doesn't need any kind of "possible
values" (there is nothing it needs to "remember"). Just provide it a string
as the argument, and the output is the result.

A class dealing with anything thats not actually stored inside of it but
acts as an intermediary (from accessing files al the way down to hardware)
does not (need to) have any "possible values" to act upon either.

Post by T
So a "class" is a declaration of a custom structure of
a collection of variables.

Nope. That would just be another structure. The difference is that a
class (normally) also has methods (functions) to work with those variables
(properties).

Also, a class can have *internal* (private) variables[3] that you can only
access by way of a method - which means that those internal variables are
not properties (that you can read from and/or write to).

[3] Though a language like Python does not offer such "private" variables :
all of them directly accessible, making them properties.

Post by T
The name "class" is pulled out of someone's ear and you just have to live
with the obscure meaning they have attached to it.

Just like any word ? :-)

My pet peeve ? "Obsolete". It has got two rather different (not even
partially overlapping) definitions.

Post by T
say (-5..5).rand.truncate.abs**3

I hope you notice that you are implicitily using a build-in object there
(there is no class name present), the one dealing with values.

Also notice that that example mixes together function names with special
function symbols ("**") that you most likely won't be able to define for
your own class(es).

Post by T
Which means to picks out a random number between -5 and 5

Not quite. The "pick a random number" from a provided range is the *second*
step. Storing that range into a "variable" is the first. You might be
able to do different things with that range than just to grab a random value
from it.

Regards,
Rudy Wieser

[T]

This post might be inappropriate. Click to display it.

[R.Wieser]

T,

Post by T
Oh good lord you have a gift for teaching.

Thank you. I've been told that I've got a bit of a knack for it. But its
nice to hear once in a while. :-)

Post by T
Speaking of googling, it does not help that "raku" is also a form of
pottery.

I know what you mean. And it doesn't help that Google often includes
"sounds like" and or "is related to" (or something like that) results
a-plenty (with just a few results that actually contain the asked-for words
in 10+ pages of crap - with no way to disable it) . :-(

Post by T
I remember a college professor trying to get us to
think Negative --> Positive, but he gave us as all
the schematics are written the other way.

Yup. A true "bug with seniority". But, in the end it does not matter
much for most cases (don't tell that to the electro-plating guys though
:-) ).

Post by T
It is not as if I wanted the tutorial to explain
how OO worked, but a link as to how an explanation
would have been nice. Your explanation would have
been perfect too and no extraneous words either.

Just keep in mind that I have given a rather terse / basic one. You might
still find a thing or two that I have never stumbled over myself.

Post by T
And I night point out that the (ha ha) tutorial
was for Raku, it need to explain how OO was
implemented into Raku, not leave it to guess work.

For me one or more annotated examples showing how something is used always
works well ("now what happens if I change /this/ into /that ..." *Crash*
"Oh well, I guess I should not do that than" :-) ). I'm always in awe of
people who can just read a chapter outof a book and than know how, in
theory, something works.

Post by T
I just discovered that if I want to write to values
inside an Object, I have to declare the variable inside
the object as "rw" (read write). They are "ro" (read
only) by default.

I think you need to investigate that a bit further. Although a read-only
/property/ sounds like something thats usable, not being able to alter,
inside the object, the underlying /variable/ doesn't.

IOW, although its possible that a /property/ can be set to RW, RO or even
WO, all an objects methods should always be able to read and write the
underlaying variable.

Having said that, I would rather have RW as the default mode for it.

Post by T
Thank you!

You're welcome.

Post by T

The rest (implementation) is language dependant.

Did the tutorial forget something? AAAAAAHHHHH !!!!!

Honestly ? I wouldn't know.

But as you have already found, a Raku object can limit access to its
properties (and thus most likely also has private variables and
methods(!) ). In Python objects on the other hand nothing is private,
/everything/ (properties, variables as well as methods and functions) is
accessible from the outside.

IOW, although both have classes, they work differently.

Regards,
Rudy Wieser

[T]

Post by R.Wieser

Post by T

The rest (implementation) is language dependant.

Did the tutorial forget something? AAAAAAHHHHH !!!!!

Honestly ? I wouldn't know.

NOOOOOOOOO?? Tell me it isn't so!!!!

:-)

Post by R.Wieser
But as you have already found, a Raku object can limit access to its
properties (and thus most likely also has private variables and
methods(!) ). In Python objects on the other hand nothing is private,
/everything/ (properties, variables as well as methods and functions) is
accessible from the outside.
IOW, although both have classes, they work differently.

Ya, and that is why the (ha ha) tutorial need
to state such.

BTW, in my write up, I include zillions of examples

[T]

BTW, in my write up, I include zillions of examples

You will love this one. Use your sense of humor reading it:

class BadMath {
has Int $.A;
has Int $.B;

method BadAdd() {
my $Clinker = (-5..5).rand.truncate;
return $!A + $!B + $Clinker;
}
}


The above will get you a "participation trophy" EVERY
TIME! Well, almost every time.

[T]

The rest (implementation) is language dependant.

Did the tutorial forget something? AAAAAAHHHHH !!!!!

[Kaz Kylheku]

Post by T
Hi All,
Windows
I know from other sources that this call is to a function
in Kernel32.dll.
https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/ns-sysinfoapi-memorystatusex

That's the descritpion of the structure used.

Post by T
But where on the page does it state such (kernel32.dll)?
Am I going blind?

That's under the associated function:

https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-globalmemorystatusex

Past the code sample, under Requirements

[T]

https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-globalmemorystatusex

Post by Kaz Kylheku
Past the code sample, under Requirements

Hi Kaz,

Ha!

Post by Kaz Kylheku
DLL Kernel32.dll

They made that obscure to find. Now I know where
to look. You'd think they'd put that at the top.

Thank you!

-T