Whats the PB equivalent for boolean

[dige]

I'm beginning to love the Purifier! Now I've found a memoryleak
that I have since ages.
This brings me to the question about: which is the correct type
of data equivalent for boolean?

BOOL can be True or False, is'nt it? Sound like it needs only one Byte
or less...
So is the right PB equivalent for boolean Byte.b?

There is a fixed code below, to check if a screensave is activ
or not. It works also with Status.b as Byte. But the Purifier
recognize a corrupt stack after calling it.

Code: Select all

Procedure.L CheckIsScreenSaverActiv()
  Protected Status.L, success.b, Bool.b
  ; Win32hlp: SPI_GETSCREENSAVEACTIVE Determines whether screen saving is enabled.
  ; The parameter must point To BOOL variable that receives TRUE If enabled,
  ; or FALSE otherwise.
  
  SystemParametersInfo_( #SPI_GETSCREENSAVEACTIVE, #Null, @Status, #Null )
  ;SystemParametersInfo_( #SPI_GETSCREENSAVEACTIVE, #Null, @Bool, #Null )  

  ProcedureReturn Status
EndProcedure

Debug CheckIsScreenSaverActiv()

[DarkDragon]

BOOL is not equal to bool. BOOL is an int. So its 32bit.

[srod]

A BOOL variable could use as little as 1 bit, but SystemParametersInfo_() is clearly writing a 32-bit integer here.

[Trond]

Better use .i for all variables for optimum performance.

[dige]

@Trond: If you use api calls, it's better to use .l if necessary.
Because that 'fix' the data type to 4 Byte Integer.

[blueznl]

There's no real boolean type in PureBasic.

http://www.xs4all.nl/~bluez/purebasic/p ... htm#floats
http://www.xs4all.nl/~bluez/purebasic/p ... and_binary

[netmaestro]

A reference I find useful:

http://msdn.microsoft.com/en-us/library/Aa383751

[ts-soft]

@Trond: If you use api calls, it's better to use .l if necessary.
Because that 'fix' the data type to 4 Byte Integer.

Only in a structure, here is integer the best choice.

[Lewis]

I believe the preferred way to implement boolean is that
0 = FALSE
and NOT FALSE = -1

Since NOT FALSE = TRUE then TRUE = -1.
It follows that NOT TRUE = 0.

Unfortunately there are not many languages that implement boolean that way.

Food for thought ...?

Cheers,
Lewis

[blueznl]

Well, PureBasic assumes 0 = false, and not-zero is true... as far as I know -1 is not zero, so...

[DarkDragon]

Guys.. the problem is solved. So many other topics could need your help .

[blueznl]

Those other questions are too difficult for me

[Lewis]

Well, PureBasic assumes 0 = false, and not-zero is true... as far as I know -1 is not zero, so...

:roll: Very observant of you, blueznl! However, the value not-zero is impossible to use directly in calculations, unlike a TRUE value of -1, which in certain circumstances can also improve code readability. Tips: Code and run X = NOT 0, and then code and run Y = NOT -1.

Cheers,
Lewis

[Demivec]

Well, PureBasic assumes 0 = false, and not-zero is true... as far as I know -1 is not zero, so...

:roll: Very observant of you, blueznl! However, the value not-zero is impossible to use directly in calculations, unlike a TRUE value of -1, which in certain circumstances can also improve code readability. Tips: Code and run X = NOT 0, and then code and run Y = NOT -1.

There is more than one way to flip a boolean value.

Code: Select all

;using bitwise NOT
x = 0
x = ~ x
Debug x
x = ~ x
Debug x
Debug "----"

;using bitwise XOR
x = 0
x ! 1
Debug x
x ! 1
Debug x

[Lewis]

Well, PureBasic assumes 0 = false, and not-zero is true... as far as I know -1 is not zero, so...

:roll: Very observant of you, blueznl! However, the value not-zero is impossible to use directly in calculations, unlike a TRUE value of -1, which in certain circumstances can also improve code readability. Tips: Code and run X = NOT 0, and then code and run Y = NOT -1.

There is more than one way to flip a boolean value.

Code: Select all

;using bitwise NOT
x = 0
x = ~ x
Debug x
x = ~ x
Debug x
Debug "----"

;using bitwise XOR
x = 0
x ! 1
Debug x
x ! 1
Debug x

Sure, although this doesn't contribute much to the TRUE/FALSE thread (for what that academic conversation is worth).