Beginner difficulties linking X app

trinity

I'm trying to write a little X app as a learner's experiment using x11/motif and having difficulties linking my program during compilation.

Here's my Makefile:

[abridged]
CFLAGS = -g
program: $(SOURCE)
        $(CC) $(CFLAGS) -o $@ \
                -DMOTIF -I/usr/pkg/include/ -I/usr/X11R7/include/ \
                -L/usr/pkg/lib/ -L/usr/X11R7/lib/ -lXm -lXt -lX11 \
                $(SOURCE)

I'm not having any trouble with preprocessing so the includes are fine but I am having trouble with the linking stage. Normal compilation spits my ELF out fine but fails to run with ./program: Shared object "libXm.so.4" not found. Static compilation says the following:

ld: /tmp//cclT5oNm.o: in function `activate':
/home/trinity/src/program/program.c:181: undefined reference to `XtVaAppInitialize'
ld: /home/trinity/src/program/program.c:190: undefined reference to `XmCreatePushButton'
ld: /home/trinity/src/program/program.c:191: undefined reference to `XtManageChild'
ld: /home/trinity/src/program/program.c:192: undefined reference to `_XmStrings'
ld: /home/trinity/src/program/program.c:192: undefined reference to `XtAddCallback'
ld: /home/trinity/src/program/program.c:195: undefined reference to `XtRealizeWidget'
ld: /home/trinity/src/program/program.c:196: undefined reference to `XtAppMainLoop'
ld: /tmp//cclT5oNm.o: in function `button_pressed':
/home/trinity/src/program/program.c:207: undefined reference to `XtAppSetExitFlag'
*** Error code 1

I'm pretty lost in terms of what's going wrong. Any help would be appreciated.

rvp

trinity Normal compilation spits my ELF out fine but fails to run with ./program: Shared object "libXm.so.4" not found

For this, you have to add these linker flags to your compile cmd. line: -Wl,-rpath=/usr/X11R7/lib -Wl,-rpath=/usr/pkg/lib because /usr/X11R7/lib and /usr/pkg/lib are not in the dynamic linker's default search path.

trinity Static compilation says the following:

This is a more complicated case. For static linking, you'll have to bring in every library object needed by the binary and its main libraries (except libc) explicitly, and in dependency-order (Ie. if liba.a requires objects in libb.a, then you'll need to supply -la -lb; the other way will fail with undefined references errors).

It's a bit of a pain, all this, (you have to run ldd on the binary/shared object, then lorder and tsort etc.--in the bad ol' days I recall having to add the same library twice to get all the dependencies resolved!) so here's a ready-made command line:

cc -static -I/usr/pkg/include -I/usr/X11R7/include -o motif motif.c \
	-L/usr/pkg/lib -L/usr/X11R7/lib \
	-lXm -lXmu -lXt -lSM -lICE -lXext -lpng16 -lz -lbz2 \
	-lXft -lfontconfig -lfreetype -lexpat -lXrender -lX11 \
	-lxcb -lXau -lXdmcp -lXrandr -ljpeg -lm

trinity

rvp Thank you very much! This fixes my problem perfectly. I thought the -L flags would be enough for the linker, I didn't know I had to configure the runtime path too. Next time I'll read the man pages more closely.

rvp

trinity I thought the -L flags would be enough for the linker, I didn't know I had to configure the runtime path too.

Adding -rpath= is how NetBSD-folks like to do it. On Linux, you would add the search paths to /etc/ld.so.conf. There are 2 other mechanisms: a) the slightly obscure $ORIGIN, and b) LD_LIBRARY_PATH= env. var. which most people know about.

trinity This fixes my problem perfectly.

OK. But consider contributing a motif.pc file for pkgsrc, so that you can just do pkg-config [--static] --libs and get this goop automatically. (I don't see why kids today should be forced to walk uphill both ways to get to their log-cabin schools like we had to.)

Start by locating the .pc files for the direct dependencies of mwm using: readelf -d mwm | grep NEEDED. See if mwm compiles/runs with just those when you use pkg-config ... to link it. All indirect dependencies, pkg-config should resolve automatically.