How to tell programmatically if my launch daemon is currently running on macOS?

Question

From an app written in C++, how can I tell that my launch daemon is currently running? And preferably how to get its PID?

For instance, if I run the following in the terminal:

launchctl list com.example.MyService                             

I get a JSON output, where it gives me the PID of the daemon process.

Having studied the source code for launchctl, I came up with the following:

const char *label = "com.example.MyService";

launch_data_t msg = launch_data_alloc(LAUNCH_DATA_DICTIONARY);
launch_data_dict_insert(msg, launch_data_new_string(label), LAUNCH_KEY_GETJOB);

launch_data_t resp = launch_msg(msg);
launch_data_free(msg);

if(resp != NULL)
{
    launch_data_type_t tt = launch_data_get_type(resp);
    if(tt == LAUNCH_DATA_DICTIONARY)
    {
        launch_data_t pid_data =
            launch_data_dict_lookup(resp, LAUNCH_JOBKEY_PID);
        if (pid_data)
        {
           if (launch_data_get_type(pid_data) == LAUNCH_DATA_INTEGER)
           {
               pid_t pid = launch_data_get_integer(pid_data);

               //...
           }
        }
    }
    else if(tt == LAUNCH_DATA_ERRNO)
    {
        int nErr = launch_data_get_errno(resp);
        
        //ESRCH = 3 = No such process
    }

    launch_data_free(resp);
}
else
{
    //No such
}

But when I run the code above for my launch daemon "label", I get my launch_data_type_t returned as LAUNCH_DATA_ERRNO and launch_data_get_errno returns ESRCH (like I showed above.)

What am I doing wrong?