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jqn
 Post subject: Clear Structures
PostPosted: Tue Aug 08, 2006 1:57 pm 
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Code updated for 5.20+ (better to use ClearStructure(), especially when the structure contains strings, array, list or map which have been allocated internally by PureBasic)

Hi,
A little piece of code:
Code:
Structure mystruc
  field1.s
  field2.l
  field3.q
  field4.f
  field5.d
EndStructure

Macro showit
  PrintN(Str(Len(mystruc\field1))+" : "+mystruc\field1)
  PrintN(Str(mystruc\field2))
  PrintN(Str(mystruc\field3))
  PrintN(StrF(mystruc\field4))
  PrintN(StrD(mystruc\field5))
  PrintN("size "+Str(SizeOf(mystruc)))
  PrintN("")
EndMacro

Global mystruc.mystruc

OpenConsole()
mystruc\field1 = "STRING DATA FIELD 1"
mystruc\field2 = 2006
mystruc\field3 = 123456789
mystruc\field4 = 987654321
mystruc\field5 = -987654321
PrintN("BEFORE")
showit

base = @mystruc
For n=0 To SizeOf(mystruc)-1
  PokeB(base+n,0)
Next
PrintN("AFTER")
showit

Input()
End
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Guimauve
 Post subject:
PostPosted: Tue Aug 08, 2006 2:56 pm 
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Little bit more simple.

Regards
Guimauve

Code:
Structure mystruc
   field1.s
   field2.l
   field3.q
   field4.f
   field5.d
EndStructure

Macro showit
   PrintN(Str(Len(mystruc\field1))+" : "+mystruc\field1)
   PrintN(Str(mystruc\field2))
   PrintN(StrQ(mystruc\field3))
   PrintN(StrF(mystruc\field4))
   PrintN(StrD(mystruc\field5))
   PrintN("size "+Str(SizeOf(mystruc)))
   PrintN("")
EndMacro

Global mystruc.mystruc

OpenConsole()
mystruc\field1 = "STRING DATA FIELD 1"
mystruc\field2 = 2006
mystruc\field3 = 123456789
mystruc\field4 = 987654321
mystruc\field5 = -987654321
PrintN("BEFORE")
showit

; base = @mystruc
; For n=0 To SizeOf(mystruc)-1
   ; PokeB(base+n,0)
; Next

RtlZeroMemory_(mystruc, SizeOf(mystruc))

PrintN("AFTER")
showit

Input()
End


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Deeem2031
 Post subject:
PostPosted: Tue Aug 08, 2006 4:55 pm 
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And the string..?

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netmaestro
 Post subject:
PostPosted: Tue Aug 08, 2006 9:37 pm 
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Quite right, the pointer to it is gone but the string is still there. This should zero the string as well:
Code:
Structure mystruc
   field1.s
   field2.l
   field3.q
   field4.f
   field5.d
EndStructure

Macro showit
   PrintN(Str(Len(mystruc\field1))+" : "+mystruc\field1)
   PrintN(Str(mystruc\field2))
   PrintN(StrQ(mystruc\field3))
   PrintN(StrF(mystruc\field4))
   PrintN(StrD(mystruc\field5))
   PrintN("size "+Str(SizeOf(mystruc)))
   PrintN("")
EndMacro

Global mystruc.mystruc

OpenConsole()
mystruc\field1 = "STRING DATA FIELD 1"
mystruc\field2 = 2006
mystruc\field3 = 123456789
mystruc\field4 = 987654321
mystruc\field5 = -987654321
PrintN("BEFORE")
showit

RtlZeroMemory_(@mystruc\field1, Len(mystruc\field1))
RtlZeroMemory_(@mystruc, SizeOf(mystruc))

PrintN("AFTER")
showit

Input()
End

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remi_meier
 Post subject:
PostPosted: Wed Aug 09, 2006 1:49 pm 
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I think that's not what he meant :wink:

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netmaestro
 Post subject:
PostPosted: Wed Aug 09, 2006 5:09 pm 
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Sorry - what did he mean then?

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Deeem2031
 Post subject:
PostPosted: Thu Aug 10, 2006 1:57 pm 
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You should free the memory of the string. If you zero the string the memory is still allocated.

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Psychophanta
 Post subject:
PostPosted: Thu Aug 10, 2006 3:44 pm 
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Deeem2031 wrote:
You should free the memory of the string. If you zero the string the memory is still allocated.

The topic said "clear", but not to free the structure.
And BTW, about this thread: is this a trick or a sort of a "Hello world!" example?

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helpy
 Post subject:
PostPosted: Thu Aug 10, 2006 4:08 pm 
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BUT! If you clear the string pointer in a structure, you produce a memory leak!

Test this:
Code:
Macro Pause
   MessageRequester("PAUSE", "Check memory usage in task manager")
EndMacro

Structure test
   l.l
   StructureUnion
      s.s
      ps.l
   EndStructureUnion
EndStructure

#TestLoop = 1024 * 1024

Pause
For i = 1 To #TestLoop
   a.test\s = Space(32)
   a\ps = #Null
Next i
Pause

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Psychophanta
 Post subject:
PostPosted: Thu Aug 10, 2006 4:33 pm 
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Of course, the "tip" or "trick" is very ugly, unelegant and bad done. :?

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