From mboxrd@z Thu Jan  1 00:00:00 1970
From: Shriramana Sharma <samjnaa@gmail.com>
Subject: Way to leave-out unused functions while linking to a library
Date: Tue, 23 May 2006 14:43:32 +0530
Message-ID: <200605231443.35393.samjnaa@gmail.com>
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I asked this question on this list some time back, IIRC -- how to leave-out=
=20
unused functions while linking to a library?

The normal behaviour is that if a library.c contains two functions fna() an=
d=20
fnb() and main.c calls only fna(), compiling library.c and main.c and linki=
ng=20
to form an executable will result in the fnb() function getting included in=
=20
the final executable, though it is never used in the entire course of the=20
program.

So how to stop fnb() from getting linked in?

Over at the GNU GCC list, a good soul gave us the solution. Use -

=2Dffunction-sections -fdata-sections=20

as compiler options and=20

=2D-gc-sections=20

as a linker option. If you are calling the linker indirectly via the compil=
er=20
gcc (i.e. if you are directly creating executables using gcc without a=20
separate call to ld) then give it the options:=20

=2Dffunction-sections -fdata-sections -Wl,--gc-sections=20

[exactly as it is, with the comma] so that the compiler passes the appropri=
ate=20
option on to the linker. This method worked for me!

=2D-=20

Tux #395953 resides at http://samvit.org
playing with KDE 3.51 on SUSE Linux 10.1
$ date [] CCE +2006-05-23 W21-2 UTC+0530

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