On Sun, 7 Jun 2020, Vict wrote:
Hello. Sorry if I didn't study the documentation well, but I don't understand
the following aspect: why does libtool not link to its own la archives when
linking with a -lname key?
Since you mention /usr/local/lib, can you confirm that LDFLAGS
includes -L/usr/local/lib or that this argument was otherwise supplied
to libtool?
Let's link a test program with libmy:
$ libtool --tag=CXX --mode=link g++ -o test_app test_app.o -lmy
test_app does not become dependent on libflt and libEGL (they are not in the
dynamic section labeled "NEEDED".
Linking test_app with absolute path to libmy does:
$ libtool --tag=CXX --mode=link g++ -o test_app test_app.o
/usr/local/lib/libmy.la
but relying on absolute path is bad. I can’t know in advance
where the library will be installed (/usr/lib, /usr/local/lib, ...).
By "know in advance", do you mean that as a software developer you
can't know the configuration of some other system while building, or
do you mean that the libraries may be installed to some random
locations?
Note that when libtool is used to install libraries, it may re-link
the libraries so that the results are different than with
"--mode=link".
You should also consider that the operating system may or may not
search the directory containing the shared libraries. If it does not
search the directory (e.g. /usr/local/lib in your case) and there is
no run search path in the dependent library, then the dependent
program won't run.
You should confirm if the libtool you are using is as delivered from
the FSF release, or if it is a modified version. Modified versions
which change how library dependencies are treated abound.
Bob
--
Bob Friesenhahn
bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,http://www.GraphicsMagick.org/
Public Key, http://www.simplesystems.org/users/bfriesen/public-key.txt
