[lldb-dev] Debugee Unable to Open Window Due to "No available video device"

Jim Ingham via lldb-dev lldb-dev at lists.llvm.org
Thu Nov 9 18:45:02 PST 2017

Xcode (on OS X) uses the lldb API to launch processes of all sorts including ones that have widows, and has windows open, so this is not a general lldb problem.  

lldb doesn’t do all that much magic to launch processes, it just calls posix_spawnp (on OS X) or fork & exec on Linux.  I would be surprised it it is something special about lldb’s launching.  OTOH since you are only passing XDG_RUNTIME_DIR, there’s some environment variable that specifies the window server connection that you’re missing.  I haven’t done X11 programming for ages, but don’t you need to pass DISPLAY?  Anyway, you might try to pass all the variables from your process to the process you are launching and see if that works.


> On Nov 9, 2017, at 6:19 PM, Jeremiah via lldb-dev <lldb-dev at lists.llvm.org> wrote:
> When using the LLDB API to launch a process from within a program that
> has opened a window, I am unable to open a window in the child
> process. When the child is using SDL I get "SDL Error: No available
> video device"  and when the child is using GLX I get "Failed to open X
> display"
> I was also getting "error: XDG_RUNTIME_DIR not set in the environment"
> but I solved that by setting XDG_RUNTIME_DIR appropriately. However,
> this did not fix the window problem.
> I also wrote a small test case to demonstrate the problem I'm having
> and I hosted it here:
> https://github.com/CaptainKraft/lldb-bug/blob/master/main.cpp
> Posting the source in the email thread didn't seem like the best
> approach, but if you'd like the source via email, I'll be happy to
> reply with it.
> There are probably a few ways to get around this issue by launching
> the process myself and attaching using the LLDB API, but it seems to
> me like there would be a way to do this by using just the API. It
> would also make the code more difficult to maintain across multiple
> platforms.
> Is there some way I can use the LLDB API to launch a process without
> preventing the child from opening a window?
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