Re: [PATCH 4/4] gnulib: import select

[Mike Frysinger <vapier@gentoo.org>]

On 09 Jun 2021 13:27, Pedro Alves wrote:
> On 2021-06-08 5:52 a.m., Mike Frysinger via Gdb-patches wrote:
> > On 07 Jun 2021 08:29, Tom Tromey wrote:
> >>>>>>> "Mike" == Mike Frysinger via Gdb-patches <gdb-patches@sourceware.org> writes:
> >>
> >> Mike> A few sims use this to emulate the syscall & provide network
> >> Mike> functionality.
> >>
> >> Thank you, I think this is ok.
> >>
> >> There are some gnulib modules that don't work well for gdb.
> >> The only one I can really remember is 'stat'.  Hopefully select isn't
> >> one of them :)
> > 
> > that would be unfortunate, but i guess we'll find out.  i'm not sure how we
> > can balance these tensions short of each project starting to carve out their
> > own gnulib ports.
> 
> I think that on Windows, gnulib's select module does something very similar to 
> what we do with ser-mingw.c's gdb_select:
> 
> ~~~
> /* On Windows, gdb_select is implemented using WaitForMulpleObjects.
>    A "select thread" is created for each file descriptor.  These
>    threads looks for activity on the corresponding descriptor, using
>    whatever techniques are appropriate for the descriptor type.  When
>    that activity occurs, the thread signals an appropriate event,
>    which wakes up WaitForMultipleObjects.
> ~~~
> 
> I've always feared that gnulib's select module would conflict with that,
> but I don't know for sure.  In theory, we should be able to replace all
> that code by using gnulib's select instead, though I'm not sure gnulib
> handles some particulars like Ctrl-C interruption.

why do you think it would conflict ?  the file doesn't seem to use select()
at all, and ser-mingw is always enabled for mingw targets.  seems like the
func would just be ignored.

> I think we can avoid some pain of someone tests the import on Windows before
> merging to master.

it's already merged ;)

gdb.exe links for me for i686-w64-mingw32, but i don't really have any way of
testing it runs, let alone run test suite.
-mike