EMA C#: OmmDate object modified during the for-each iteration

Frederic

Real-Time: For Real-Time SDK C#, looks like the OmmDate object will be modified during the for-each iteration, could you please verify if this is a bug? Take this RIC as example /HCEIX4 .

public void OnRefreshMsg(RefreshMsg refreshMsg, IOmmConsumerEvent consumerEvent)

{

OmmDate? date = null;

Console.WriteLine(refreshMsg);

foreach (var field in refreshMsg.Payload().FieldList())

{

if (field.Code == Data.DataCode.BLANK)

continue;

switch (field.FieldId){

case 16:

date = field.OmmDateValue();

Console.WriteLine($"date (in-place): {date}");

break;

}

}

Console.WriteLine($"date (after-foreach): {date}");

}

This function is used to extract one specific field with fieldId == 16 (i.e., TRADE_DATE) into my date object. The output I get is this:
date (in-place): 29 OCT 2024
date (after-foreach): (blank data)

wasin.w

Hello @Frederic

I found the client has submitted the GitHub issue 291 to the RTSDK team. The RTSDK team has investigated the issue, and the team confirms that it is by the design of the API, not a bug.

RTSDK Team comment:

For performance reasons RTSDK EMA Library reuses objects whenever possible. That's why objects returned from data access methods are transient and short-lived. Values that they contain are not guaranteed to live outside of scope.

In the case described above it is application's responsibility to copy data its needs from the object returned by the OmmDateValue() method.

Example Code:

Each application might have different business requirement, so there is no universal solution to copy data out of the FieldEntry.OmmXXValue() methods that fits all purposes.

There are various ways to copy data such as using .NET DateOny object or string, etc. as follows:

DateOny object (available on .NET 6 and .NET 8)

DateOnly date = DateOnly.FromDateTime(DateTime.Now);
Console.WriteLine(refreshMsg);
foreach (var field in refreshMsg.Payload().FieldList())
{
    if (field.Code == Data.DataCode.BLANK)
        continue;
    switch (field.FieldId)
    {
        case 16:
            //date = field.OmmDateValue().ToString();
            date = new DateOnly(field.OmmDateValue().Year,
                        field.OmmDateValue().Month,
                        field.OmmDateValue().Day);
            Console.WriteLine($"date (in-place): {date.ToString("dd MMM yyyy")}");
            break;
    }
}
Console.WriteLine($"date (after-foreach): {date.ToString("dd MMM yyyy")}");

String:

string date = "";
Console.WriteLine(refreshMsg);
foreach (var field in refreshMsg.Payload().FieldList())
{
    if (field.Code == Data.DataCode.BLANK)
        continue;

    switch (field.FieldId)
    {
        case 16:
            date = field.OmmDateValue().ToString();
            
            Console.WriteLine($"date (in-place): {date.ToString()}");
            break;
    }
}
Console.WriteLine($"date (after-foreach): {date}");