Tutorial on DllCall() & DllStructs

[OtenMoten]

Hello dear community,

$calldata=DllCall("Kernel32.dll","int","GetDiskFreeSpaceW","wstr","C:\","dword*",$SectorsP erCluster,"dword*",$BytesPerSector,"dword*",$NumberOfFreeClusters,"dword*",$TotalNumberOfClusters)

Would it be correct if I am calling the variables in the DllCall as 'dummys' ?
It seems to me to be because you can fill in any variables and that the variables are only needed because the field shouldn't be empty.

I altered the DllCall in:

$calldata = DllCall("Kernel32.dll","int","GetDiskFreeSpaceW","wstr","C:\","dword*",NULL ,"dword*",NULL,"dword*",NULL,"dword*",NULL)

 

The result in

_ArrayDisplay($calldata, "Caption")

is the same as the top one.
I have some struggle in my mind - this is why I am asking.

I am right?

Kind regards

Edited October 27, 2017 by OtenMoten

[Danyfirex]

Null is designed for wstr/str and Objects.

I would do it this ways.

#include <Array.au3>
$calldata = DllCall("Kernel32.dll","int","GetDiskFreeSpaceW","wstr","C:\","dword*",0 ,"dword*",0,"dword*",0,"dword*",0)
_ArrayDisplay($calldata)

;you also can do this
Local $tCluster=DllStructCreate("dword value")
$calldata = DllCall("Kernel32.dll","int","GetDiskFreeSpaceW","wstr","C:\","ptr",DllStructGetPtr($tCluster) ,"dword*",NULL,"dword*",NULL,"dword*",NULL)
MsgBox(0,"",$tCluster.value)

 

Saludos

[Skysnake]

 

[caramen]

Thanks for this.