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ActiveX and time-slicing

Question asked by VRFuser on Apr 27, 1999
Latest reply on Apr 27, 1999 by VRFuser

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At 12:02 27/04/99 +0200, you wrote:
>
>----- Original Message -----
>From: Juan Vera <jvera@mdr.indra-espacio.es>
>To: <hpvxd_xc@hpislsup.lvld.hp.com>
>Sent: Monday, April 26, 1999 10:50 AM
>Subject: VRf: ActiveX and time-slicing
>
>
>> If an ActiveX control event handler is enabled and a defined event arises,
>> VEE always calls the involved VEE function (where the event is treated) in
>a
>> no-time-slicing fashion.
>>
>> Does anybody know how to invoke a VEE event function in a time-slicing
>basis ?
>>
>> Thanks in advance.
>
>
>Use a global var in your event handler which changes its state by the event.
>Then return to standard VEE and in a continous loop check the state of this
>var. If the var is set ( event occurred) then you can call the vee-function
>and it will time slice.
>

Ok but this approach does not take benefit of the event oriented programming.

-------------------------------------------------
| Juan Vera                         |
| E-mail:     jvera@mdr.indra-espacio.es     |
| Phone:     34-913 963 986               |
| Fax:          34-913 963 912               |
| Earth Stations Department               |
| INDRA ESPACIO S.A.                    |
| Mar Egeo 4, Pol. Ind. 1               |
| San Fernando de Henares               |
| 28850 MADRID                         |
| SPAIN                              |
-------------------------------------------------

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VRFuser Apr 26, 1999 6:17 PM
Mark Correct
Correct Answer
That is because it is implemented correctly. An event to an application is
like an interrupt to a MCU. It should be handled as quickly as possible,
everything else should be put on hold.

I am currently struggling with a similar problem. I have an interrupt
handler that is caused by an SRQ. It is a user function that is called by a
formula control pin, which makes it non-multithreaded. The problem is that
if this function calls any other function that was executing when the
interrupt occured, vee will lock up. I don't know if this happens with the
event handlers, but you may want to see.

-----Original Message-----
From: Juan Vera [mailto:jvera@mdr.indra-espacio.es]
Sent: Tuesday, April 27, 1999 7:48 AM
To: Georg Nied
Cc: hpvxd_xc@hpislsup.lvld.hp.com
Subject: Re: ActiveX and time-slicing

At 12:02 27/04/99 +0200, you wrote:
>
>----- Original Message -----
>From: Juan Vera <jvera@mdr.indra-espacio.es>
>To: <hpvxd_xc@hpislsup.lvld.hp.com>
>Sent: Monday, April 26, 1999 10:50 AM
>Subject: VRf: ActiveX and time-slicing
>
>
>> If an ActiveX control event handler is enabled and a defined event
arises,
>> VEE always calls the involved VEE function (where the event is treated)
in
>a
>> no-time-slicing fashion.
>>
>> Does anybody know how to invoke a VEE event function in a time-slicing
>basis ?
>>
>> Thanks in advance.
>
>
>Use a global var in your event handler which changes its state by the
event.
>Then return to standard VEE and in a continous loop check the state of this
>var. If the var is set ( event occurred) then you can call the vee-function
>and it will time slice.
>

Ok but this approach does not take benefit of the event oriented
programming.

-------------------------------------------------
| Juan Vera                         |
| E-mail:     jvera@mdr.indra-espacio.es     |
| Phone:     34-913 963 986               |
| Fax:          34-913 963 912               |
| Earth Stations Department               |
| INDRA ESPACIO S.A.                    |
| Mar Egeo 4, Pol. Ind. 1               |
| San Fernando de Henares               |
| 28850 MADRID                         |
| SPAIN                              |
-------------------------------------------------
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VRFuser Apr 26, 1999 6:17 PM
Mark Correct
Correct Answer
That is because it is implemented correctly. An event to an application is
like an interrupt to a MCU. It should be handled as quickly as possible,
everything else should be put on hold.

I am currently struggling with a similar problem. I have an interrupt
handler that is caused by an SRQ. It is a user function that is called by a
formula control pin, which makes it non-multithreaded. The problem is that
if this function calls any other function that was executing when the
interrupt occured, vee will lock up. I don't know if this happens with the
event handlers, but you may want to see.

-----Original Message-----
From: Juan Vera [mailto:jvera@mdr.indra-espacio.es]
Sent: Tuesday, April 27, 1999 7:48 AM
To: Georg Nied
Cc: hpvxd_xc@hpislsup.lvld.hp.com
Subject: Re: ActiveX and time-slicing

At 12:02 27/04/99 +0200, you wrote:
>
>----- Original Message -----
>From: Juan Vera <jvera@mdr.indra-espacio.es>
>To: <hpvxd_xc@hpislsup.lvld.hp.com>
>Sent: Monday, April 26, 1999 10:50 AM
>Subject: VRf: ActiveX and time-slicing
>
>
>> If an ActiveX control event handler is enabled and a defined event
arises,
>> VEE always calls the involved VEE function (where the event is treated)
in
>a
>> no-time-slicing fashion.
>>
>> Does anybody know how to invoke a VEE event function in a time-slicing
>basis ?
>>
>> Thanks in advance.
>
>
>Use a global var in your event handler which changes its state by the
event.
>Then return to standard VEE and in a continous loop check the state of this
>var. If the var is set ( event occurred) then you can call the vee-function
>and it will time slice.
>

Ok but this approach does not take benefit of the event oriented
programming.

-------------------------------------------------
| Juan Vera                         |
| E-mail:     jvera@mdr.indra-espacio.es     |
| Phone:     34-913 963 986               |
| Fax:          34-913 963 912               |
| Earth Stations Department               |
| INDRA ESPACIO S.A.                    |
| Mar Egeo 4, Pol. Ind. 1               |
| San Fernando de Henares               |
| 28850 MADRID                         |
| SPAIN                              |
-------------------------------------------------
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VRFuser Apr 26, 1999 7:58 PM
Mark Correct
Correct Answer
> I am currently struggling with a similar problem. I have an interrupt
> handler that is caused by an SRQ. It is a user function that
> is called by a
> formula control pin, which makes it non-multithreaded. The
> problem is that
> if this function calls any other function that was executing when the
> interrupt occured, vee will lock up. I don't know if this
> happens with the
> event handlers, but you may want to see.
>

This problem appears to be due to the fact that a call to a function will block
until any earlier call to the same function has completed. Performing the
second call non-multithreaded does not allow VEE to return to complete the
first call.

The "easy" solutions include:

- Duplicate the function and dedicate one copy to the interrupt handler. Not
so easy if the function is large and complex or if it calls other functions
that could result in additional lockups.

- Are you using the Formula control pin to force a non-multithreaded handler?
If not, can you modify the handler to call the formula in a multithreaded
manner?

Let us know if you come up with a good solution.

Regards,
Bruce Wenner
HP St. Paul
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VRFuser Apr 26, 1999 7:58 PM
Mark Correct
Correct Answer
> I am currently struggling with a similar problem. I have an interrupt
> handler that is caused by an SRQ. It is a user function that
> is called by a
> formula control pin, which makes it non-multithreaded. The
> problem is that
> if this function calls any other function that was executing when the
> interrupt occured, vee will lock up. I don't know if this
> happens with the
> event handlers, but you may want to see.
>

This problem appears to be due to the fact that a call to a function will block
until any earlier call to the same function has completed. Performing the
second call non-multithreaded does not allow VEE to return to complete the
first call.

The "easy" solutions include:

- Duplicate the function and dedicate one copy to the interrupt handler. Not
so easy if the function is large and complex or if it calls other functions
that could result in additional lockups.

- Are you using the Formula control pin to force a non-multithreaded handler?
If not, can you modify the handler to call the formula in a multithreaded
manner?

Let us know if you come up with a good solution.

Regards,
Bruce Wenner
HP St. Paul
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VRFuser Apr 26, 1999 9:02 PM
Mark Correct
Correct Answer

----- Original Message -----
From: Juan Vera <jvera@mdr.indra-espacio.es>
To: <hpvxd_xc@hpislsup.lvld.hp.com>
Sent: Monday, April 26, 1999 10:50 AM
Subject: VRf: ActiveX and time-slicing

> If an ActiveX control event handler is enabled and a defined event arises,
> VEE always calls the involved VEE function (where the event is treated) in
a
> no-time-slicing fashion.
>
> Does anybody know how to invoke a VEE event function in a time-slicing
basis ?
>
> Thanks in advance.

Use a global var in your event handler which changes its state by the event.
Then return to standard VEE and in a continous loop check the state of this
var. If the var is set ( event occurred) then you can call the vee-function
and it will time slice.

Hope that became clear - aint got much time now
Georg Nied
Software Development
51149 Koeln
Germany
gn-software@gmx.de
ICQ 23490440
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VRFuser Apr 26, 1999 9:02 PM
Mark Correct
Correct Answer

----- Original Message -----
From: Juan Vera <jvera@mdr.indra-espacio.es>
To: <hpvxd_xc@hpislsup.lvld.hp.com>
Sent: Monday, April 26, 1999 10:50 AM
Subject: VRf: ActiveX and time-slicing

> If an ActiveX control event handler is enabled and a defined event arises,
> VEE always calls the involved VEE function (where the event is treated) in
a
> no-time-slicing fashion.
>
> Does anybody know how to invoke a VEE event function in a time-slicing
basis ?
>
> Thanks in advance.

Use a global var in your event handler which changes its state by the event.
Then return to standard VEE and in a continous loop check the state of this
var. If the var is set ( event occurred) then you can call the vee-function
and it will time slice.

Hope that became clear - aint got much time now
Georg Nied
Software Development
51149 Koeln
Germany
gn-software@gmx.de
ICQ 23490440
Like • Show 0 Likes0
Actions
VRFuser Apr 27, 1999 5:48 AM
Mark Correct
Correct Answer
At 12:02 27/04/99 +0200, you wrote:
>
>----- Original Message -----
>From: Juan Vera <jvera@mdr.indra-espacio.es>
>To: <hpvxd_xc@hpislsup.lvld.hp.com>
>Sent: Monday, April 26, 1999 10:50 AM
>Subject: VRf: ActiveX and time-slicing
>
>
>> If an ActiveX control event handler is enabled and a defined event arises,
>> VEE always calls the involved VEE function (where the event is treated) in
>a
>> no-time-slicing fashion.
>>
>> Does anybody know how to invoke a VEE event function in a time-slicing
>basis ?
>>
>> Thanks in advance.
>
>
>Use a global var in your event handler which changes its state by the event.
>Then return to standard VEE and in a continous loop check the state of this
>var. If the var is set ( event occurred) then you can call the vee-function
>and it will time slice.
>

Ok but this approach does not take benefit of the event oriented programming.

-------------------------------------------------
| Juan Vera                         |
| E-mail:     jvera@mdr.indra-espacio.es     |
| Phone:     34-913 963 986               |
| Fax:          34-913 963 912               |
| Earth Stations Department               |
| INDRA ESPACIO S.A.                    |
| Mar Egeo 4, Pol. Ind. 1               |
| San Fernando de Henares               |
| 28850 MADRID                         |
| SPAIN                              |
-------------------------------------------------
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