Re: [Qemu-devel] How to I trigger a rebuild?

[Joachim Durchholz]

Am 14.04.19 um 20:12 schrieb Peter Maydell:
> On Sun, 14 Apr 2019 at 17:08, Joachim Durchholz <address@hidden> wrote:
> > Am 14.04.19 um 03:15 schrieb Max Filippov:
> > > On Sat, Apr 13, 2019 at 8:28 AM Joachim Durchholz <address@hidden> wrote:
> > > > I did the usual ./configure; make dance.
> > > > Then modified a source file (ui/curses.c), called make again, but didn't
> > > > see curses.c recompiled, and the change was indeed ineffective.
> > > > make clean; make didn't help either.
> > >
> > > Perhaps you don't have CONFIG_CURSES enabled?
> > > Did you call configure with --enable-curses ?
> >
> > Strange. "make help" tells me that everything is enabled by default if
> > possible, and I didn't tell configure to do anything specific.
> >
> > But I find that curses is disabled indeed.
> > Heh. An explicit --enable-curses tells me it was missing the dev version
> > of ncurses.
>
> Configure's default behaviour is "enable everything that we can
> enable, but don't complain about not enabling optional features
> which we can't build (eg because of missing -dev libraries)".
> For "insist that foo is built and error out if it can't be done",
> use "--enable-foo". For "definitely don't build foo even if we
> could", use --disable-foo.

Well, that's what I guessed after the fact... it didn't occur to me that 
"what's possible" was defined as "what libraries are available".
Now that I know this, I know what to watch out for.

> > However... even with curses enabled, "make" does not do anything  after
> > modifying ui/curses.c.
> > In fact, just "make" tell's me I should have run ./config (WTF I did??),
> > and "make all"
> > But after ./configure is recompiles everything... nothing of this is
> > something that "make" should do, so I'm pretty confused.
>
> This sounds like maybe you got confused somewhere along the line
> about whether you'd (re-)run configure or not (or didn't
> do a 'make clean' after running configure with the curses
> support enabled).

Actually I got confused about where I was building.
I had set up things for an out-of-tree build but accidentally hit "make" 
in the source tree.

> The other thing that might confuse you is that make will try
> to spot when it needs to rerun configure and will rerun it
> for you.

Oh dear. That didn't happen to me, but I see the trap-in-waiting.

> I recommend doing builds only in a separate directory, by the way:
>   mkdir build
>   (cd build && ../configure [configure args])
>   make -C build -j8

Yep, doing that already.

Regards,
Jo