Linking problems in Linux

[joeprogrammer]

I was over at a friend's house, trying to compile the latest development version of Wesnoth (v1.18), and on an old version of Ubuntu. There were all sorts of dependancy issues, and I managed to work through most of them. However, when I was trying to configure SDL_image, I ran into a problem.

It needed the following libraries: libpng, libjpeg, and libtiff. I got to work downloading and installing them, and when I was done, I tried running the configure script again. It didn't complain about libpng and libtiff now, but it still couldn't find libjpeg.

I tried copying libjpeg.so to every lib directory I could think of, and yet it still refused to find it. I tried echoing LD_LIBRARY_PATH; there was nothing in it, so I added /usr/local/lib to it. Still not working. I looked for ld.so.config; it didn't exist. I created it, added /usr/local/lib, and ran configure again. Still no luck.

I also tried a number of configure options, but I couldn't get it to work. I've googled, and although this problem is common, I still can't point the configure script to the right directory.

One thing to note is that ./configure does create a makefile, but it gives a warning that "JPEG support is disabled", and then make gives a link error.

[psychopath]

I've had trouble linking with libjpeg aswell. Sadly, I never fixed it, so I can't help.

[joeprogrammer]

Well, did you get it compiled? At least libjpeg compiled, so the only problem is that I can't get configure to locate libjpeg.so.

EDIT: Do you think I could edit the makefile for SDL_image? I'm not really familiar with editing makefiles manually, but if someone could tell me which line, that would be great.

[psychopath]

Well, the weird thing with my problem was that my distro came with libjpeg.so already installed (so I didn't need to compile it), but I still had linker problems.

I looked for ld.so.config

I thought the file was lib.so.conf, or was the "ig" a typo?
EDIT: actually, now that I think about it, maybe it is ".config". I can't remember, and i'm too lazy to boot into Linux to find out.

Are you running ldconfig after adding the directory to lib.so.conf?

Try adding /usr/lib to your config paths, or are you absolutly sure it's in /usr/local/lib?

[CornedBee]

Doesn't the configure file have a --with-jpeg option that you can supply with the full path to libjpeg.so?

[joeprogrammer]

I thought the file was lib.so.conf, or was the "ig" a typo?

Yes, that was a typo.

Are you running ldconfig after adding the directory to lib.so.conf?

I already tried that, no luck.

Doesn't the configure file have a --with-jpeg option that you can supply with the full path to libjpeg.so?

Maybe, I don't know, as I'm not at my friend's computer right now. I'll try that. I just thought of running apt-get install SDL_image; that might be easier.

[joeprogrammer]

Dunno if this helps; I grabbed a section from the configure script (even though I can't really read shell scripting)

  have_libjpeg=yes
fi
    
    if test x$have_libjpeg = xyes; then
        if test x$enable_jpg = xyes; then
            cat >>confdefs.h <<\_ACEOF
#define LOAD_JPG 1
_ACEOF

        fi
        LIBS="-ljpeg $LIBS"
            case "$host" in
            *-*-darwin*) # FIXME when Mac OS X ships with libjpeg
                jpg_lib=''
                ;;
            *-*-cygwin* | *-*-mingw32*)
                jpg_lib='jpeg.dll'
                ;;
            *)
                for path in /usr/lib /usr/local/lib; do
                    if test x$jpg_lib = x; then
                        jpg_lib=`ls -- $path/libjpeg.so.[0-9][0-9] 2>/dev/null | sort -r | sed 's/.*\/\(.*\)/\1/; q'`
                    fi
                done
                ;;
        esac
Always prints the message below....
    elif test x$enable_jpg = xyes; then
        { echo "$as_me:$LINENO: WARNING: *** Unable to find JPEG library (http://www.ijg.org/)" >&5
echo "$as_me: WARNING: *** Unable to find JPEG library (http://www.ijg.org/)" >&2;}
        { echo "$as_me:$LINENO: WARNING: JPG image loading disabled" >&5
echo "$as_me: WARNING: JPG image loading disabled" >&2;}

I have the file "libjpeg.so" in /usr/lib and /usr/local/lib (a few others, but these are the main ones).

[Perspective]

usually the <file>.so is just a symlink to some versioned file <file>.so.05. try ls -l to see if the symlink is dead, if you just copied the file to that dir you might not have the proper library file.

[joeprogrammer]

usually the <file>.so is just a symlink to some versioned file <file>.so.05. try ls -l to see if the symlink is dead, if you just copied the file to that dir you might not have the proper library file.

Nope, I checked. It's the actual file, and it's not pointing anywhere.

[Perspective]

>jpg_lib=`ls -- $path/libjpeg.so.[0-9][0-9]

It looks like that is explicitly looking for one

[joeprogrammer]

It looks like that is explicitly looking for one

Yeah, the only problem is that I don't know shell scripting. Do you think I could just modify it to point to the existing path?

[Perspective]

worth a shot. Or just create a symlink with libjpeg.so.5.5 -> libjpeg.so so the regex matches something. I'm not sure if thats even the problem though, just something that popped out at me.