libtool drops dylibs at link time

[jeremyhu (Jeremy Huddleston Sequoia)]

VLC fails to build with opencv support because opencv's pkg-config file lists paths to dylibs rather than -l<lib> arguments. This should work just fine, but glibtool doesn't like it. It just drops the dylibs on the floor when creating the command line to envoke:

/opt/local/bin/glibtool  --tag=CXX   --mode=link /usr/bin/clang++   -pipe -Os -arch x86_64 -stdlib=libc++ -D_INTL_REDIRECT_MACROS -I/opt/local/var/macports/build/_Users_jeremy_src_macports_trunk_dports_multimedia_VLC-devel/VLC-devel/work/VLC-devel-2.1.99/contrib/include -Wall -Wextra -Wsign-compare -Wundef -Wpointer-arith -Wvolatile-register-var -fvisibility=hidden -ffast-math -funroll-loops -fomit-frame-pointer -avoid-version -module -export-symbols-regex ^vlc_entry -shrext .dylib -no-undefined ../../compat/libcompat.la ../../src/libvlccore.la  -rpath '/opt/local/lib/vlc/plugins/video_filter'  -L/opt/local/lib -Wl,-headerpad_max_install_names -arch x86_64 -Wl,-headerpad_max_install_names -L/opt/local/var/macports/build/_Users_jeremy_src_macports_trunk_dports_multimedia_VLC-devel/VLC-devel/work/VLC-devel-2.1.99/contrib/lib -o libopencv_example_plugin.la  libopencv_example_plugin_la-opencv_example.lo /opt/local/lib/libopencv_calib3d.dylib /opt/local/lib/libopencv_contrib.dylib /opt/local/lib/libopencv_core.dylib /opt/local/lib/libopencv_features2d.dylib /opt/local/lib/libopencv_flann.dylib /opt/local/lib/libopencv_gpu.dylib /opt/local/lib/libopencv_highgui.dylib /opt/local/lib/libopencv_imgproc.dylib /opt/local/lib/libopencv_legacy.dylib /opt/local/lib/libopencv_ml.dylib /opt/local/lib/libopencv_nonfree.dylib /opt/local/lib/libopencv_objdetect.dylib /opt/local/lib/libopencv_photo.dylib /opt/local/lib/libopencv_stitching.dylib /opt/local/lib/libopencv_superres.dylib /opt/local/lib/libopencv_ts.a /opt/local/lib/libopencv_video.dylib /opt/local/lib/libopencv_videostab.dylib

*** Warning: Linking the shared library libopencv_example_plugin.la against the
*** static library /opt/local/lib/libopencv_ts.a is not portable!
glibtool: link: rm -fr  .libs/libopencv_example_plugin.exp
glibtool: link: /usr/bin/nm  .libs/libopencv_example_plugin_la-opencv_example.o   | sed -n -e 's/^.*[	 ]\([BCDEGRST][BCDEGRST]*\)[	 ][	 ]*_\([_A-Za-z][_A-Za-z0-9]*\)$/\1 _\2 \2/p' | sed '/ __gnu_lto/d' | /usr/bin/sed 's/.* //' | sort | uniq > .libs/libopencv_example_plugin.exp
glibtool: link: /usr/bin/grep -E -e "^vlc_entry" ".libs/libopencv_example_plugin.exp" > ".libs/libopencv_example_plugin.expT"
glibtool: link: mv -f ".libs/libopencv_example_plugin.expT" ".libs/libopencv_example_plugin.exp"
glibtool: link: sed -e 's,^,_,' < .libs/libopencv_example_plugin.exp > .libs/libopencv_example_plugin-symbols.expsym
glibtool: link: /usr/bin/clang++  -o .libs/libopencv_example_plugin.dylib -bundle  .libs/libopencv_example_plugin_la-opencv_example.o   ../../compat/.libs/libcompat.a -L/opt/local/lib -L/opt/local/var/macports/build/_Users_jeremy_src_macports_trunk_dports_multimedia_VLC-devel/VLC-devel/work/VLC-devel-2.1.99/contrib/lib ../../src/.libs/libvlccore.dylib -lintl -lidn -liconv -lm /opt/local/lib/libopencv_ts.a  -Os -arch x86_64 -stdlib=libc++ -Wl,-headerpad_max_install_names -arch x86_64 -Wl,-headerpad_max_install_names   -Wl,-exported_symbols_list,.libs/libopencv_example_plugin-symbols.expsym
Undefined symbols for architecture x86_64:
  "_cvClearMemStorage", referenced from:
      Filter(filter_t*, picture_t*) in libopencv_example_plugin_la-opencv_example.o
  "_cvCreateMemStorage", referenced from:
      OpenFilter(vlc_object_t*) in libopencv_example_plugin_la-opencv_example.o
  "_cvGetSeqElem", referenced from:
      Filter(filter_t*, picture_t*) in libopencv_example_plugin_la-opencv_example.o
  "_cvHaarDetectObjects", referenced from:
      Filter(filter_t*, picture_t*) in libopencv_example_plugin_la-opencv_example.o
  "_cvLoad", referenced from:
      OpenFilter(vlc_object_t*) in libopencv_example_plugin_la-opencv_example.o
  "_cvRectangle", referenced from:
      Filter(filter_t*, picture_t*) in libopencv_example_plugin_la-opencv_example.o
  "_cvReleaseHaarClassifierCascade", referenced from:
      CloseFilter(vlc_object_t*) in libopencv_example_plugin_la-opencv_example.o
  "_cvReleaseMemStorage", referenced from:
      CloseFilter(vlc_object_t*) in libopencv_example_plugin_la-opencv_example.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

[cooljeanius (Eric Gallager)]

Cc Me!

[skymoo (Adam Mercer)]

That sounds like a problem with opencv's pkg-config file, surely it should specify the link flags needed to link the library, which libtool then passes these onto the compiler, not the path to the libraries?

[stromnov (Andrey Stromnov)]

Probably fixed by jeremyhu at r117530.

My system:

$ port installed opencv
The following ports are currently installed:
  opencv @2.4.8_2+eigen+java+opencl+python27+qt4 (active)

and

$ cat /opt/local/lib/pkgconfig/opencv.pc
# Package Information for pkg-config

prefix=/opt/local
exec_prefix=${prefix}
libdir=
includedir_old=${prefix}/include/opencv
includedir_new=${prefix}/include

Name: OpenCV
Description: Open Source Computer Vision Library
Version: 2.4.8
Libs: -L${exec_prefix}/lib  -lopencv_calib3d -lopencv_contrib -lopencv_core -lopencv_features2d -lopencv_flann -lopencv_gpu -lopencv_highgui -lopencv_imgproc -lopencv_legacy -lopencv_ml -lopencv_nonfree -lopencv_objdetect -lopencv_ocl -lopencv_photo -lopencv_stitching -lopencv_superres -lopencv_ts -lopencv_video -lopencv_videostab
Cflags: -I${includedir_old} -I${includedir_new}

[jeremyhu (Jeremy Huddleston Sequoia)]

Replying to stromnov@…:

Probably fixed by jeremyhu at r117530.

No, that was a workaround in opencv.

This is a bug in glibtool.

[jeremyhu (Jeremy Huddleston Sequoia)]

Replying to ram@…:

That sounds like a problem with opencv's pkg-config file, surely it should specify the link flags needed to link the library, which libtool then passes these onto the compiler, not the path to the libraries?

No, it's not a bug in opencv as I already explained. You can clearly see in the command line that the linker flags *ARE* being passed to glibtoo, and glibtool is not passing them on to the linker.

[michaelld (Michael Dickens)]

Given now old this ticket is, I'm guessing it's been "fixed" by newer releases ... for example libtool is at 2.4.7 & I'm updating it to 2.4.8 ; opencv (2) has been replaced by opencv3 ... I'm going to close this ticket as "fixed" ... but if someone can show otherwise then please reopen and post info as to what's still going on.

[jmroot (Joshua Root)]

No sign of a fix for this in the commits since 2.4.6. Of course if it hasn't been reported upstream, it should be.