[ moving from automake@ ]
Hello,
* LCID Fire wrote on Sun, Dec 14, 2008 at 07:51:07PM CET:
> Ralf Wildenhues wrote:
> > Elsewhere, flags like AM_LDFLAGS are denoted as global. In that case,
> > it is meant to say that, unlike program_LDFLAGS, which applies to
> > 'program' only, the flags apply to all binaries created by this
> > Makefile.am (that themselves don't have per-target flags which override
> > the "global" AM_LDFLAGS). Makes sense a bit?
> IMO global is used incorrectly here because it is just per Makefile.
> Global initially made me think it really is for all Makefiles.
Good point. WDYT about the patch below?
Can I get a real name for THANKS?
> > Variables are not transported between Makefile files the way you think.
> > In the above example, the first line is redundant, and AM_CFLAGS will
> > have the value of "whatever" in this Makefile. In 'somedir', it will
> > have no particular value unless you set it there.
> So basically variables are not ever transported between Makefiles.
Correct.
BTW, there is a reason this is not done: portability. The Autoconf
manual has a chapter about why portably transporting variables between
makefiles is a major pain.
> AFAIU setting a variable in configure.in provides this set of
> variable/value to all Makefiles.
Correct. But you can override this in individual Makefile.am files
by also setting the variable explicitly there.
> And the variable again is NOT globally modifiable
> since setting the variable in one Makefile is something another makefile
> will not recognize
Correct.
> (thus I'd say upon writing a local copy of every variable is created).
Well, what really happens is that, with
AC_SUBST([VARIABLE])
in configure.ac, and
VARIABLE = my value from Makefile.am
in Makefile.am, the Makefile.in will contain
VARIABLE = @VARIABLE@
...
VARIABLE = my value from Makefile.am
and thus the latter wins.
> > Hope that helps.
> Thanks, helped a great deal. These concepts were not really obvious to
> me when reading the documentation.
Good documentation patches are always welcome. :-)
Cheers,
Ralf
Do not use 'global' for makefile-wide settings.
* doc/automake.texi (Linking, Libtool Flags)
(Program and Library Variables, Flag Variables Ordering):
Reword instances of `global variables' that really mean
makefile-wide ones.
Report by LCID Fire <[email protected]>.
diff --git a/doc/automake.texi b/doc/automake.texi
index fa0a277..e7ae93b 100644
--- a/doc/automake.texi
+++ b/doc/automake.texi
@@ -4586,9 +4586,8 @@ Sometimes, multiple programs are built in one directory
but do not share
the same link-time requirements. In this case, you can use the
@co...@var{prog}_ldadd} variable (where @var{prog} is the name of the
program as it appears in some @code{_PROGRAMS} variable, and usually
-written in lowercase) to override the global @code{LDADD}. If this
-variable exists for a given program, then that program is not linked
-using @code{LDADD}.
+written in lowercase) to override @code{LDADD}. If this variable exists
+for a given program, then that program is not linked using @code{LDADD}.
@vindex maude_LDADD
For instance, in GNU cpio, @code{pax}, @code{cpio} and @code{mt} are
@@ -5256,8 +5255,8 @@ Libtool Manual} for more options) should appear before
the mode
selection on the command line; in @file{Makefile.am}s they should
be listed in the @sa...@var{library}_libtoolflags} variable.
-If @sa...@var{library}_libtoolflags} is not defined, the global
-...@code{am_libtoolflags} variable is used instead.
+If @sa...@var{library}_libtoolflags} is not defined, then the variable
+...@code{am_libtoolflags} is used instead.
These flags are passed to libtool after the @option{--t...@var{tag}}
option computed by Automake (if any), so
@@ -5495,11 +5494,11 @@ of any library built by your package. Doing so will
ensure that
@item maude_LDFLAGS
This variable is used to pass extra flags to the link step of a program
-or a shared library. It overrides the global @code{AM_LDFLAGS} variable.
+or a shared library. It overrides the @code{AM_LDFLAGS} variable.
@item maude_LIBTOOLFLAGS
This variable is used to pass extra options to @command{libtool}.
-It overrides the global @code{AM_LIBTOOLFLAGS} variable.
+It overrides the @code{AM_LIBTOOLFLAGS} variable.
These options are output before @command{libtool}'s @option{--mo...@var{mode}}
option, so they should not be mode-specific options (those belong to
the compiler or linker flags). @xref{Libtool Flags}.
@@ -10768,7 +10767,7 @@ has neither @code{AM_} nor per-target cousin.
Finally you should not think either that the existence of a per-target
variable implies that of an @code{AM_} variable or that of a user
variable. For instance, the @code{mumble_LDADD} per-target variable
-overrides the global @code{LDADD} variable (which is not a user
+overrides the makefile-wide @code{LDADD} variable (which is not a user
variable), and @code{mumble_LIBADD} exists only as a per-target
variable. @xref{Program and Library Variables}.
