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Date: Thu, 02 Jun 2022 19:07:14 +0300
Message-Id: <83tu93dp71.fsf@gnu.org>
From: Eli Zaretskii <eliz@gnu.org>
To: Jon Turney <jon.turney@dronecode.org.uk>
Cc: tromey@adacore.com, gdb-patches@sourceware.org
In-Reply-To: <6f7e3db5-76f4-e21d-edbd-2cd1993a7bdd@dronecode.org.uk> (message
 from Jon Turney on Thu, 2 Jun 2022 15:19:21 +0100)
Subject: Re: [PATCH] Handle encoding failures in Windows thread names
References: <20220421143926.2550856-1-tromey@adacore.com>
 <6f7e3db5-76f4-e21d-edbd-2cd1993a7bdd@dronecode.org.uk>
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> Date: Thu, 2 Jun 2022 15:19:21 +0100
> From: Jon Turney <jon.turney@dronecode.org.uk>
> 
> > diff --git a/gdb/nat/windows-nat.c b/gdb/nat/windows-nat.c
> > index bd1b9459145..7a4e804f891 100644
> > --- a/gdb/nat/windows-nat.c
> > +++ b/gdb/nat/windows-nat.c
> > @@ -119,12 +119,19 @@ windows_thread_info::thread_name ()
> >         HRESULT result = GetThreadDescription (h, &value);
> >         if (SUCCEEDED (result))
> >   	{
> > -	  size_t needed = wcstombs (nullptr, value, 0);
> > -	  if (needed != (size_t) -1)
> > +	  int needed = WideCharToMultiByte (CP_ACP, 0, value, -1, nullptr, 0,
> > +					    nullptr, nullptr);
> > +	  if (needed != 0)
> >   	    {
> > -	      name.reset ((char *) xmalloc (needed));
> > -	      if (wcstombs (name.get (), value, needed) == (size_t) -1)
> > -		name.reset ();
> > +	      BOOL used_default = FALSE;
> > +	      gdb::unique_xmalloc_ptr<char> new_name
> > +		((char *) xmalloc (needed));
> > +	      if (WideCharToMultiByte (CP_ACP, 0, value, -1,
> > +				       new_name.get (), needed,
> > +				       nullptr, &used_default) == needed
> > +		  && !used_default
> > +		  && strlen (new_name.get ()) > 0)
> > +		name = std::move (new_name);
> >   	    }
> >   	  LocalFree (value);
> >   	}
> 
> This is probably wrong on Cygwin (as the target encoding should be 
> Cygwin's conception of the locale, not the Windows codepage).

What does CP_ACP does on Cygwin? is it different from what that does
in native Windows programs?

Anyway, for Cygwin I think we should replace CP_ACP with CP_UTF8,
don't you think?