[SOLVED] libPNG version conflicts, how to solve?

rdx · 12-03-2015, 06:10 AM

My Slackware64 14.1 box came with libpng version 1.4 and I have just DL'd the latest version, 1.6 (which has installed under /usr/local, whereas the others, 1.4, 1.2, 3.0, are under /usr). I am trying to compile one of the contrib/example files as such:

gcc pngpixel.c -o pngpixel -I/usr/local/include -L/usr/local/lib -lpng16 -lm
which seems to work until I try to run the program, which gives me this error message:
pngpixel: error while loading shared libraries: libpng16.so.16: cannot open shared object file: No such file or directory
The library in question, libpng16.so.16 is definitely in /usr/local/lib.
Can someone please tell me what I am doing wrong? Thanks.

pan64 · 12-03-2015, 07:40 AM

you may need to set LD_LIBRARY_PATH to /usr/local/lib
the problem is that your app cannot find that lib.

NevemTeve · 12-03-2015, 02:04 PM

Don't forget to run ldconfig (as root) after installing something. You can even see what does it do:

Code:

ldconfig -v | less

Keith Hedger · 12-03-2015, 02:23 PM

And make sure that /usr/local/lib is in the /etc/ld.so.conf file

rdx · 12-03-2015, 02:29 PM

Quote:

Originally Posted by pan64

you may need to set LD_LIBRARY_PATH to /usr/local/lib
the problem is that your app cannot find that lib.

That almost worked! I had to export LD_LIBRARY_PATH too, small detail. Thanks.

rdx · 12-03-2015, 02:37 PM

Quote:

Originally Posted by NevemTeve

Don't forget to run ldconfig (as root) after installing something. You can even see what does it do:

Code:

ldconfig -v | less

Okay, that didn't work UNTIL I added that path to /etc/ld.so.conf and now it does, Thanks.

rdx · 12-03-2015, 02:37 PM

Quote:

Originally Posted by Keith Hedger

And make sure that /usr/local/lib is in the /etc/ld.so.conf file

Excellent, I think that's the answer I was looking for, Thanks.