_kf_
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Vix 1.0 | Vmware Server | Multithreading

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Hey guys. to controle my machines i use vix 1.0 with vmware-server. in sme documents i've read, that this version should be thread safe, but my application c/c++ crashes each time, when i call a vix functions. can someone help?

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Fozzi
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Can you process a VIX_HostConnect?

If not, check if you are using the proper DLL's that fir to your installed VMware Server/Worktation product.

View solution in original post

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Fozzi
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Can you process a VIX_HostConnect?

If not, check if you are using the proper DLL's that fir to your installed VMware Server/Worktation product.

View solution in original post

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_kf_
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yeah. in a single thread - my code works fine. no problems.

pls see my code.... http://phpfi.com/342066

Maybe i've an old version? i use the vix api from the latest vmware-server 1.0.6 installation.

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_kf_
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VC++ 8 | Windows XP..

i think the problem is definitly the multithreading...

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Fozzi
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Enthusiast

Took a look at your code.

EnterCriticalSection() and LeaveCriticalSection() are direct Windows API calls, but this has nothing to do with multithreading.

I'am programming with PowerBasic and also use CriticalSection-Calls, but not while accessing VIX-functions, only when setting global variables.

Besides. Vix_HostConnect delivers a hosthandle, you can use this value all of the time everywhere in your program (if global), no need to encapsulate in a critical section.

(1) call Vix_HostConnect

(2) define a function you can use multithreaded (detecting powerstate or so)

(3) call your mt-function with virtual machine A

(4) call your mt-function with virtual machine B

Use critical sections within the mt-functions to change variables (e.g. virtual machine power state or so; maybe you stored this to an array)

_kf_
Contributor
Contributor

Okay that means, i have to wrap all orginal VIX functions for multithreading using critical sections?

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Fozzi
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You have to wrap the VIX functions for multithreading.

You have to wrap variable-accesses with critical sections. This can be within your VIX-functions or any other code.

VIX functions are threadsafe, this means you don't have to care if you are calling a VIX function from a main program, or from a threaded function.

Personally i don't like critical sections, because it takes a long time. I've compared critical section with a simple long integer variable locking mechanism, my version works 10 times faster.

If you have some BASIC knowledge, have fun with this:

'----


' Function GLock

' locking for global variables

' in 0 => reset

' -1 => set lock, wait infinitely

' +value => set lock, wait

' out %True => lock/reset success

' %False => lock failed

'----


Function GLock(Opt ByVal Init As Long ) As Long

Static LockVar As Dword

Local lResult As Long

Local cnt As Long

'initialize/reset lock

If Init = 0 Then

lResult = InterlockedExchange( LockVar, 0 )

Function = %True

Exit Function

End If

'set lock

If Init < 0 Then

Do While LockVar <> 0

Sleep 10

Loop

lResult = InterlockedIncrement( LockVar )

Function = %True

End If

'wait for lock

If Init > 0 Then

cnt = 0

Do While LockVar <> 0

Sleep 100

Incr cnt

If Init > cnt*10 Then

Function = %False

Exit Function

End If

Loop

Function = %True

End If

End Function

_kf_
Contributor
Contributor

Okay thx. vix functions are thread safe but i've to wrap all "variable-accesses" in safe section like critical-section?

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Fozzi
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Enthusiast

Now you got it.

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