slider value access

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1

Hi,

I’m writing some code which accesses a slider’s value and then increments
it.

I have some basic code:


Pt_Arg arg;

PtSetArg(&arg, Pt_ARG_GAUGE_VALUE, 0, 0);
PtGetResources(ABW_AGM130HorizontalSlider, 1, &arg);

I go through this particular code 6 times without failure. On the 7th loop
I get a “TASK EXCEPTION”.

Is there something special I need to do that I’m not?

Thanks

Dave Hurlburt

2

“David Hurlburt” <dhurlburt@faac.com> wrote in message
news:a1l02s$jgi$1@inn.qnx.com…

Hi,

I’m writing some code which accesses a slider’s value and then increments
it.

I have some basic code:


Pt_Arg arg;

PtSetArg(&arg, Pt_ARG_GAUGE_VALUE, 0, 0);
PtGetResources(ABW_AGM130HorizontalSlider, 1, &arg);

I go through this particular code 6 times without failure. On the 7th
loop
I get a “TASK EXCEPTION”.

Is there something special I need to do that I’m not?

Thanks

Dave Hurlburt

Addendum…

I just printed out the widget id value and it seems this global value
changes. Anybody have an idea how this would happen?

int lvalue = (int) ABW_AGM130HorizontalSlider;

6 times is the same - the 7th it changes. This is a global item created by
PhAB. I have no idea where to chase this one…

3

Hi David,

If you check the docs for PtGetResouces there is a warning message about
not changing the value in the widget directly it can cause strange
things to happen. Here is what the warning says :

\

Because PtGetResource() returns a pointer directly into the internals of
the widget, don’t modify the resource value directly. If you wish to
retrieve the value of a given resource and then modify that value:
1.
Get the resource.
2.
Copy the resource to a temporary variable.
3.
Modify the temporary variable.
4.
Using the modified copy, set the resource.

For example:

int *gauge_value;
PtArg_t
arg;

/* This will get the gauge value and store it in the variable gauge_value */
PtSetArg(&arg, Pt_ARG_GAUGE_VALUE, &gauge_value, 0);
PtGetResources(ABW_AGM130HorizontalSlider, 1,&arg);

/* Now modify the value for this example I am just setting it to zero */
*gauge_value = 0;

/* Now set the gauge value resource */
PtSetArg(&arg, Pt_ARG_GAUGE_VALUE, *gauge_value, 0);
PtSetResources(ABW_AGM130HorizontalSlider, 1, &arg);

You can use the PtSetResources and PtGetResources to set multiple
resources at once. The help docs shows this.


Let me know if this helps
Regards
Brenda

David Hurlburt wrote:

“David Hurlburt” <> dhurlburt@faac.com> > wrote in message
news:a1l02s$jgi$> 1@inn.qnx.com> …

Hi,

I’m writing some code which accesses a slider’s value and then increments
it.

I have some basic code:


Pt_Arg arg;

PtSetArg(&arg, Pt_ARG_GAUGE_VALUE, 0, 0);
PtGetResources(ABW_AGM130HorizontalSlider, 1, &arg);

I go through this particular code 6 times without failure. On the 7th

loop

I get a “TASK EXCEPTION”.

Is there something special I need to do that I’m not?

Thanks

Dave Hurlburt



Addendum…

I just printed out the widget id value and it seems this global value
changes. Anybody have an idea how this would happen?

int lvalue = (int) ABW_AGM130HorizontalSlider;

6 times is the same - the 7th it changes. This is a global item created by
PhAB. I have no idea where to chase this one…
\