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June 15, 2005

Building LIBGD on FreeBSD

While building Thomas Boutell's excellent libgd library (ver 2.0.33) on FreeBSD 4.11, I ran into a problem that Google shows lots of others have had, but without a solution. After configuring the library for the platform, undefined pthread variables are found: 

$ make
...
/usr/local/bin/bash ./libtool --mode=link gcc  -g -O2   -L/usr/local/lib \
   -L/usr/local/lib -o annotate  annotate.o ./libgd.la -ljpeg -lfreetype -lpng \
   -lz -lm  /usr/local/lib/libiconv.so -Wl,-rpath -Wl,/usr/local/lib
gcc -g -O2 -o .libs/annotate annotate.o /usr/local/lib/libiconv.so \
   -Wl,-rpath -Wl,/usr/local/lib  -L/usr/local/lib ./.libs/libgd.so \
   -ljpeg -lfreetype -lpng -lz -lm -Wl,--rpath -Wl,/usr/local/lib
./.libs/libgd.so: undefined reference to `pthread_mutex_unlock'
./.libs/libgd.so: undefined reference to `pthread_mutex_destroy'
./.libs/libgd.so: undefined reference to `pthread_mutex_lock'
./.libs/libgd.so: undefined reference to `pthread_mutex_init'
*** Error code 1

Looking around found no libpthread.a library - huh? - in any of its forms, but it was hard to imagine that this machine simply didn't have this facility.

Several hours of hunting this down showed the problem: pthreads are found in libc_r (the re-entrant C library). Aha! This is enabled with the -pthread flag to gcc.

I typically use a simple wrapper script around ./configure so that I can document my settings, and I just added CFLAGS="-pthread" to the ../configure-gd script:

#
# requires LIBPNG
#
#       sh ../configure-gd
#       make
#       make check
#       sudo make install
#

export CFLAGS='-pthread'   # for FreeBSD

exec ./configure \
        --without-x

The proper solution is to fix the configure.ac script to check for this properly, but it looks like very ugly territory; many flavors and variants and workarounds. Sadly, not up for that today.

I'm documenting this here mainly so Google will index it and perhaps help some future GD-builder who's been having the same problem.

Posted by steve at June 15, 2005 05:40 PM

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Comments

Well, your goal has been met. I've fought this multiple times and finally decided to give it one last go at a deep Google search. It's a shame this wasn't indexed higher as it's right on the money! Thanks much for sharing your experience.

Posted by: Tim Provencio at July 25, 2005 07:14 PM

You my friend deserve a medal, finally managed to find this post after days of trying to get GD to compile. I skipped over this bit earlier on as ./configure said it detected '-pthread' as the switch. Ah well! It compiled this time.

Thanks for that.

Posted by: Alex at September 22, 2005 09:35 PM

Very good - I'd I'll take the "wrapper tip" onboard. Must add a link to my site to give you some google juice!

Posted by: Steve Welham at October 3, 2005 07:49 AM

Dude, you the man!

setenv CFLAGS -pthreads then redid ./configure so that it read the variable and my compilation problem went away.

Posted by: Very Grateful Reader at December 1, 2005 07:46 PM

Yep, this is brilliant advice and has worked for me.

Now I'm having a similar problem when I'm trying to install and run the Perl GD library. It builds OK but all the tests fail with things like:

t/GD..........Can't load './blib/arch/auto/GD/GD.so' for module GD: /usr/local/gd-2.0.33/lib/libgd.so.2: Undefined symbol "pthread_mutex_unlock" at /usr/local/perl-5.8.4/lib/5.8.4/i386-freebsd/DynaLoader.pm line 230.
at t/GD.t line 14

Hmmmm.

Posted by: Jesse Reynolds at September 10, 2006 01:56 AM