Explain the AddRemove parameter in OnClipboardChange? Topic is solved

[NorInd]

Problem:
Explain the AddRemove parameter in OnClipboardChange?

What does it mean by Call the function after any previously registered functions?
What are previously registered functions?

Quote:

OnClipboardChange(Func , AddRemove)

AddRemove
If blank or omitted, it defaults to 1 (call the function after any previously registered functions). Otherwise, specify one of the following numbers:

1 = Call the function after any previously registered functions.
-1 = Call the function before any previously registered functions.

[boiler]

What are previously registered functions?

It means a function you had already set up to be called using OnClipboardChange(). Example:

Code: Select all

#Persistent
OnClipboardChange("FnA")
OnClipboardChange("FnB", -1)
return

FnA() {
	MsgBox, Function A
}

FnB() {
	MsgBox, Function B
}

[Lepes]

It means a function you had already set up to be called using OnClipboardChange(). Example:

I'm sorry to disturb here but I will like to learn a bit more. Are you sure that it means "a function you already set up"

I mean, Helps talk about "-1 = Call the function before any previously registered functions. ", but keep in mind that many other programs on Windows OS can register themselves on OnClipboardChange().
Windows OS maintain a list (array of callbacks) from those programs that want to be nofified on clipboards changes.

I think that a "-1" means that your program will be notified before any other program that is registered on "Windows OS". In this way you can create a "clipboard viewer/manager" that always be the first to be notified. In facts most clipboards manager do this, it changes again the content of the clipboard and the rest of programs already registered won't see the first change of the clipboard (there are techniques to do that,if you return a non zero value on your callback function, that changes won't be sent to the others registered windows, if you return zero, it will be, to be honest I don't know how it works on AHK, that's why I ask).

Return Value
If this is the last or only OnClipboardChange function, the return value is ignored. Otherwise, the function can return a non-zero integer to prevent subsequent functions from being called.

[Lepes]

-------------deleted, so nobody get wrong with the old text--------------

[just me]

@Lepes,

previously registered functions

are functions previously registered by the currently running AHK script to run whenever the clipboard's content changes, i.e. you can register various functions.

[Lepes]

@Lepes,

previously registered functions

are functions previously registered by the currently running AHK script to run whenever the clipboard's content changes, i.e. you can register various functions.

So we can not create a clipboard manager in AHK. Imaging this Scenario:
Clipboard callbacks: [ program1, AHK, program2]

We copy a text "Hello world", program1 don't touch the text and return 0, so AHK receives the text and changes to "I'm AHK" and return 0:
program1 receives "Hello world"
AHK receives "Hello world"
program2 receives "I'm AHK"
At this point I mess up the clipboard.

If we were capable of inserting on first place of the clipboard callbacks, all programs will receive "I'm AHK" that it is what is spected from a Clipboard Manager.

Don't get me wrong, I don't doubt about what you are saying, I already said that I'm a newbie on AHK, but I did a clipboard Manager con Delphi 7 with Windows Api and that's the way Windows Clipboard works. So helpfile lacks this appreciation? I mean it is not about other Clipboard registered applications?

[just me]

@Lepes, AHK is calling AddClipboardFormatListener() on Win Vista+. OnClipboardChange() defines the internal functions to be called whenever AHK receives a WM_CLIPBOARDUPDATE notification.

[Lepes]

Thank you @boiler and @just me