Detect first pass through a do-while - c++

Question

I have a do-while loop that needs to log a message once (so it doesn't clutter the log) each time its status (e.g. pass/fail) changes, but still has to do other things each time it goes through the loop. Using a simple boolean variable can basically tell you if you've already logged that message, which works once you're in a known condition. However, if you want the message to be printed the first time in either case (pass/fail), you have to account for that. For example, if you default your condition to true, and it is, in fact, true the first time, it won't log the 'True' message b/c it thinks it was already true (and vice-versa for i.c. false).
This seems like it would be a good place for a nullable boolean with i.c.=Null, but in languages where those aren't present, what's one to do?
The simplest solution I could think of would be to use an extra boolean variable like 'firstTime = True', but using that always bothers me as an elementary workaround when I feel like there should be a more delicate way to handle it. Another option is to use the breakout condition of the do-while as your initial condition for whatever variable you're using as your conditional, but that can be confusing when someone reads int status = STATUS_QUIT, and it certainly requires more explanatory comments than bool firstTime = true. A third option would be to use an enum instead of a bool and have {firstTime, true, false} or something.
Are there other reasons for using one over the other, or are there better ways of doing this?
Code example with two options I came up with:
Using bool firsttime:
bool firstTime = true, infoFound = false;
do
{
if (getInfo())
{
if (!infoFound)
{
// log it (ONCE)(important)
infoFound = true;
}
// use info (every time)
}
else if (infoFound || firstTime)
{
// log it (ONCE)(important)
infoFound = false;
firstTime = false;
}
// FYI, WaitForStatusUpdate is a blocking call...
} while (STATUS_QUIT != WaitForStatusUpdate());
Use the while loop 'break-out condition' as the initial condition for a check variable:
(status is updated at the end of the do-while, so the do section will not be executed ever again if status == breakOutCondition; we can use this to our advantage here and set status = breakOutContition initially - the first time through it will be breakOutCondition but any subsequent loop will be something else... Still not sure I like this as it's kind of a hack...
bool infoFound = false;
int status = STATUS_QUIT;
do
{
if (getInfo())
{
if (!infoFound)
{
// log it (ONCE)(important)
infoFound = true;
}
// use info (every time)
}
else if (infoFound || firstTime)
{
// log it (ONCE)(important)
infoFound = false;
}
status = WaitForStatusUpdate();
} while (STATUS_QUIT != status);
(I'm tagging this as c++ since that's what I'm using, but this really could apply to any language with similar constructs)

Answer 1

Wouldn't an enum be clearer?
enum State { Unknown, Pass, Fail };
State state = Unknown;
...
State newState = getInfo() ? Pass : Fail;
if (newState != state) { log(); state = newState; }

Answer 2

C++ almost has nullable booleans, boost::optional<bool> would do the trick I believe.
One common way to do this in C++ is a stream wrapper that you create in the proper context, and it remembers for example how many times it's flushed and prevents further logging from happening. You just do your logging as normal and let the stream decide whether to send it on to the wrapped stream.