CacheEntry::SetValue

Updates the value for the cache entry. Note that SetValid must be called to set the entry's valid state to true.

void SetValue(const T& value);

Parameters

value: [in] The value to test for equality against the cached value, if present. The data type T is that of the CacheEntry template instance.

Example

The following example demonstrates use of the SetValue function.

C++

Copy

ViStatus _VI_FUNC acme4321_set_BANDWIDTH(ViSession Vi, ViConstString RepCapIdentifier, ViReal64 AttributeValue)
{
    auto status = VI_SUCCESS;

    // Retrieve the cache entry for the Bandwidth attribute
    // 
    auto& entry = GetCacheEntry<ViReal64>(Vi, ACME4321_ATTR_BANDWIDTH);

    // If the value is in the cache AND is valid, simply return since we don't need to send the instrument command
    // 
    if (entry.HasValue(AttributeValue))
    {
        return status;
    }

    // If we get this far, then the new value is not in the cache, so we must communicate with the instrument to set the value
    // 
    status = viPrintf(GetVisaSession(Vi), "SENS:BAND %0.15g\n", AttributeValue);
    ReturnOnError(status);

    // The new value was successfully sent to the instrument, so update the cache
    // 
    entry.SetValue(AttributeValue);
    entry.SetValid();

    return status;
}