Experimental Physics and
Industrial Control System

[email protected] (Kay Kasemir) · Wed, 23 Feb 2000 10:56:56 -0700

At 11:27 AM 2/23/00 -0600, you wrote:
>Hi,
>
>Could someone advise me please how to control the native type of PV created
>in portable CA server
>with use of  gdd library ( pVV =  new gddScalar(gddAppType_value,
>aitEnumFloat32); )
>I mean native type which can be asked using  ca_field_type() function ..
>I have two servers running with the same PV creation, but one gives native
>type = 2 (float) and
>another gives 0 (string). Is there any way to change native type from 0 to
>2, for example? Thanks,
>
>Vladimir
> 

Hi Vladimir:

When you derive from casPV,
you can overload bestExternalType().
An example would be this:

// What should be used to retrieve the native type?
aitEnum CEpicsPV::bestExternalType() const
{
	// We have enum strings?
	if (m_enum_strings.size() > 0)
		return aitEnumEnum16;

	// Default if value's type not known, yet
	if (! m_value)
		return aitEnumFloat64;

	return m_value->primitiveType();
}

-> If I have enum strings, I prefer to be looked at as a aitEnumEnum16.
When I have a gdd, I return its type.

When I don't know yet, I return aitEnumFloat64
(Special situation here because in my case the PV
 might just have been created but has not received a value, yet.
 I won't admit that this is a bit crummy)

-Kay

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System