Re: Built sources always regenerated

[Tom Tromey]

>>>>> "Braden" == Braden McDaniel <address@hidden> writes:

Braden> Forget about BUILT_SOURCES and *_DEPENDENCIES. The sources I'm building
Braden> get #include'd by browser.cpp. As such, checking of browser.cpp's
Braden> dependencies should cause them to get (re)generated, right?

Braden> But it doesn't. If I remove BUILT_SOURCES, the files don't get
Braden> generated before browser.cpp gets compiled. Why not?

Automake dependency tracking information is computed as a side effect
of compilation.  So, the first time things are compiled, it has no way
of knowing about dependencies on generated files.

BUILT_SOURCES is a hack to get around this.  It basically inserts a
'make $(BUILT_SOURCES)' before targets like 'all'.  (It would be nice
to have per-{executable,library} BUILT_SOURCES...)

I didn't look into this too deeply but I would guess that it is more
make-related than automake-related.  You can add rules to the
Makefile.am to help with debugging, eg:

hack:
        $(MAKE) $(BUILT_SOURCES)

Then in theory 'make hack' should reproduce the problem you're seeing.
If that doesn't happen then something weird and perhaps
automake-related is going on.  If it does happen, you can try plain
old Makefile debugging with 'make -d'.

Tom