BTW, I'm writing this up into a larger message that explains the big picture and how everything ties together, I play to post that in a separate thread. Maybe today, if I finish it, otherwise tomorrow.
On Mon, Sep 22, 2014 at 11:30 AM, Zachary Turner <ztur...@google.com> wrote: > The only way to wait for a process to exit is calling > WaitForSingleObject() with the handle. You can specify a timeout to that > function, and INFINITE is one possible value. However, it seems like the > primary use case for LLDB waiting for a process to exit is to fire off the > exit callback asynchronously. In that case Windows, like other platforms, > will probably need to create a background thread, then > WaitForSingleObject() on the background thread, then fire the callback > after it returns. > > What I was thinking is have the HostProcess provide a method called > BlockUntilExit() which can be used anywhere (even from the main thread) > should the caller desire it, but when launching a process we would create a > thread for on each platform that just calls this method on the HostProcess, > then issues the callback. This would unify alot of code currently spread > across the different Host.[cpp/mm] files. > > One thing that still eludes me though, is that when processes are launched > using Applescript, no monitoring thread is created, and it looks at least > like the callback is never invoked on these processes. Is this by design, > a bug, or am I misreading the code? > > On Mon, Sep 22, 2014 at 11:15 AM, Greg Clayton <gclay...@apple.com> wrote: > >> So you can get the exit status of a process using >> >> BOOL WINAPI GetExitCodeProcess(_In_ HANDLE hProcess, _Out_ LPDWORD >> lpExitCode); >> >> Is there a way to wait for the process to exit without polling? Or do you >> have to keep calling GetExitCodeProcess() until STILL_ACTIVE is not >> returned? I am guessing you can wait on the hProcess handle somehow? >> >> Anyway, it seems like we want the following when launching processes: >> >> 1 - a way to wait for a process to finish with an optional timeout (which >> defaults to infinite) >> 2 - a way to say, no need to wait for the process to finish >> >> For 1, we do what we are currently doing. The process monitor callback >> for windows will need to wait for the process to exit, then call >> GetExitCodeProcess() when done and return the value. On unix machines, we >> will reap the process and return the exit status. >> >> For 2, windows doesn't need to do anything, but we still need to reap the >> process on unix to avoid zombies. >> >> Not sure if I missed any scenarios? >> >> Greg >> >> >> > On Sep 22, 2014, at 9:33 AM, Zachary Turner <ztur...@google.com> wrote: >> > >> > Yes, but closing the handle is semantically a different operation than >> reaping a process. You can close a handle to a process while the process >> is still running and it doesn't affect anything except that it frees up >> space in your process's handle table. You can also not close a handle, and >> if the process exits nothing bad will come of it. So closing the handle is >> more tied to the lifetime of the instantiated HostProcess , and independent >> of the actual process running on ths system. >> > >> > On Sun, Sep 21, 2014 at 11:40 PM, Matthew Gardiner <m...@csr.com> >> wrote: >> > On Wed, 2014-09-17 at 00:27 -0700, Zachary Turner wrote: >> > >> > > I know Join isn't really the right word, but there's no concept of >> > > reaping a process on Windows. >> > >> > However, on Windows, isn't there still a requirement to CloseHandle that >> > handles returned by CreateProcess? >> > >> > Matt >> > >> > >> > >> > >> > >> > Member of the CSR plc group of companies. CSR plc registered in England >> and Wales, registered number 4187346, registered office Churchill House, >> Cambridge Business Park, Cowley Road, Cambridge, CB4 0WZ, United Kingdom >> > More information can be found at www.csr.com. Keep up to date with CSR >> on our technical blog, www.csr.com/blog, CSR people blog, >> www.csr.com/people, YouTube, www.youtube.com/user/CSRplc, Facebook, >> www.facebook.com/pages/CSR/191038434253534, or follow us on Twitter at >> www.twitter.com/CSR_plc. >> > New for 2014, you can now access the wide range of products powered by >> aptX at www.aptx.com. >> > >> > _______________________________________________ >> > lldb-dev mailing list >> > lldb-dev@cs.uiuc.edu >> > http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev >> >> >
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