GNU bug report logs - #78411
LDADD vs. LDFLAGS

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Bruno Haible <bruno <at> clisp.org>
To: bug-automake <at> gnu.org
Subject: LDADD vs. LDFLAGS
Date: Tue, 13 May 2025 18:59:20 +0200

[Message part 1 (text/plain, inline)]

The first paragraph in
https://www.gnu.org/software/automake/manual/html_node/Linking.html
can be interpreted in a misleading way:

  "If you need to link against libraries that are not found by configure,
   you can use LDADD to do so. This variable is used to specify additional
   objects or libraries to link with; it is inappropriate for specifying
   specific linker flags; you should use AM_LDFLAGS for this purpose."

Last week, I interpreted this as "objects or libraries" being *.o, *.a,
and *.la files. And "linker flags" as including -L and -l options.
And I concluded that I should specify the -L and -l options in
*_LDFLAGS, not in *_LDADD, variables.

But that would not work because of these Automake generated rules
and variables:

LINK = $(CCLD) $(AM_CFLAGS) $(CFLAGS) $(AM_LDFLAGS) $(LDFLAGS) -o $@
test_bind_LINK = $(CCLD) $(AM_CFLAGS) $(CFLAGS) $(test_bind_LDFLAGS) $(LDFLAGS) -o $@

test-bind$(EXEEXT): $(test_bind_OBJECTS) $(test_bind_DEPENDENCIES) $(EXTRA_test_bind_DEPENDENCIES)
        @rm -f test-bind$(EXEEXT)
        $(AM_V_CCLD)$(LINK) $(test_bind_OBJECTS) $(test_bind_LDADD) $(LIBS)


Here's a proposed slight rewording that avoids this ambiguity.

[0001-doc-Clarify-where-to-put-L-and-l-options.patch (text/x-patch, attachment)]

Message #8 received at 78411 <at> debbugs.gnu.org (full text, mbox):

From: Karl Berry <karl <at> freefriends.org>
To: bruno <at> clisp.org
Cc: 78411 <at> debbugs.gnu.org
Subject: Re: bug#78411: LDADD vs. LDFLAGS
Date: Wed, 14 May 2025 15:43:00 -0600

     If you need to link against libraries that are not found by
     @command{configure}, you can use @code{LDADD} to do so.  This variable is
    -used to specify additional objects or libraries to link with; it is
    -inappropriate for specifying specific linker flags; you should use
    -@code{AM_LDFLAGS} for this purpose.
    +used to specify additional objects or libraries to link with.
    +Libraries to link with can be indicated either as file names or
    +through @code{-L} and @code{-l} options.
    +
    +For other linker options (not @code{-L} or @code{-l}), @code{LDADD}
    +is inappropriate.  You should use @code{AM_LDFLAGS} for this purpose.

Thanks Bruno. Pushed as written. -k

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