How do I know when CreateProcess actually started a process?

Question

I'm having trouble which boils down to wishing CreateProcess were StartProcess. The trouble is that there are circumstances under which CreateProcess returns true when it created the process but the system could not start the process. For example, CreateProcess will succeed even if one of the launchee's imports cannot be resolved.

There are probably a dozen suggestions one could make depending on what exactly I hope to accomplish by having launched this process. However, I'm afraid none of those suggestions is likely to be useful because I'm not hoping to acccomplish anything in particular by having launched this process.

One example suggestion might be to call WaitForSingleObject against the process handle and then GetExitCodeProcess. But I can't wait for the process to exit because it might stick around forever.

Another example suggestion might be to call WaitForInputIdle, which would work well if I hoped to communicate with the launchee by means of a window I could reasonably expect the launchee to create. But I don't hope that and I can't reasonably expect that. For all I know, the launchee is a console process and/or will never have a message queue. As well, I can't afford to wait around (with heuristic intent) to find out.

In fact, I can't assume anything about the launchee.

To get a better idea of how I'm thinking here, let's look at the flip side of the issue. If the process doesn't start, I want an error code that tells me how I might advise the user. If the imports all resolved and the main thread realizes it's about to jump into the CRT startup code (or equivalent), and the error code I get back is ERROR_SUCCESS, great! But I'm actually disinterested in the launchee and merely wish to provide a good user experience in the launcher.

Oh, and one more thing: I want this to be simple. I don't want to write a debugger. :-)

Ideas?

Answer 1

This question has gone so long without an answer that I suspect it's safe to conclude that the answer is: "You can't."

Answer 2

One example suggestion might be to call WaitForSingleObject against the process handle and then GetExitCodeProcess. But I can't wait for the process to exit because it might stick around forever.

Why don't you wait for the process handle for some reasonable time. If the timer expires before the handle is signaled, you can presume the process is up and running. If the handle is signaled first, and the exit code is good, then you can presume it ran and completed successfully.

In case you haven't seen it, the CreateProcess vs started problem was mentioned in Raymond Chen's blog.

Honestly, if you're not willing to accept heuristics (like, "it hasn't ended with a failure code after three seconds, therefore we assume all is well") then you're going to have to write a 'debugger', by which I mean inspect the internals of the launched process.