CGAL users discussion list

[Joachim Reichel <>]

Hi,

On 04/20/2011 08:57 AM, pascal8361 wrote:
> I forgot the link command:

I still don't see it ;-) BTW if you call cmake with 
-DCMAKE_VERBOSE_MAKEFILE=ON
it will print the executed commands.

> I am building the project with cmake and I am using the CGAL flag to build
> statically when calling cmake .

Doing this within cmake might be difficult. I would call the link command 
manually.

For the Alpha_shapes_2 demo the link command looks as follows:

/usr/bin/c++   -frounding-math -g
/CMakeFiles/Alpha_shapes_2.dir/Alpha_shapes_2.o
/CMakeFiles/Alpha_shapes_2.dir/qrc_Alpha_shapes_2.o  -o Alpha_shapes_2 
-rdynamic
-lCGAL_Qt4 -lCGAL -lgmpxx -lmpfr -lgmp -lboost_thread-mt lQtOpenGL -lQtGui
-lQtCore -lGLU -lGL -lX11 -lXext -lQtOpenGL -lQtScript -lQtGui -lQtXml 
-lQtCore
-lCGAL_Qt4 -lCGAL -lgmpxx -lmpfr -lgmp -lboost_thread-mt -lQtOpenGL -lQtGui
-lQtCore -lGLU -lGL -lX11 -lXext -lQtScript -lQtXml

First get rid of the repeated and unneeded libraries (it might be necessary to
reorder the libraries):

/usr/bin/c++   -frounding-math -g
CMakeFiles/Alpha_shapes_2.dir/Alpha_shapes_2.o
CMakeFiles/Alpha_shapes_2.dir/qrc_Alpha_shapes_2.o  -o Alpha_shapes_2 
-rdynamic
-lCGAL_Qt4 -lCGAL -lgmpxx -lmpfr -lgmp -lboost_thread-mt -lQtOpenGL -lQtGui
-lQtCore -lGLU -lGL -lX11 -lXext

Now use -Wl,-Bstatic and -Wl,-Bdynamic to force the use of static libraries:

/usr/bin/c++   -frounding-math -g
CMakeFiles/Alpha_shapes_2.dir/Alpha_shapes_2.o
CMakeFiles/Alpha_shapes_2.dir/qrc_Alpha_shapes_2.o  -o Alpha_shapes_2 
-rdynamic
-Wl,-Bstatic -lCGAL_Qt4 -lCGAL -lgmpxx -lmpfr -lgmp -lboost_thread-mt 
-lQtOpenGL
-lQtGui -lQtCore -lGLU -lGL -lX11 -lXext -Wl,-Bdynamic
/usr/bin/ld: cannot find -lQtOpenGL
/usr/bin/ld: cannot find -lQtGui
/usr/bin/ld: cannot find -lQtCore
/usr/bin/ld: cannot find -lGL
collect2: ld returned 1 exit status

It turns out that on my machine there is no static version of the Qt and GL
libraries. Again, use -Wl,-Bstatic and -Wl,-Bdynamic to use the dynamic
libraries for these (and for -lX11 too):

/usr/bin/c++   -frounding-math -g
CMakeFiles/Alpha_shapes_2.dir/Alpha_shapes_2.o
CMakeFiles/Alpha_shapes_2.dir/qrc_Alpha_shapes_2.o  -o Alpha_shapes_2 
-rdynamic
-Wl,-Bstatic -lCGAL_Qt4 -lCGAL -lgmpxx -lmpfr -lgmp -lboost_thread-mt
-Wl,-Bdynamic -lQtOpenGL -lQtGui -lQtCore -Wl,-Bstatic -lGLU  -Wl,-Bdynamic 
-lGL
-lX11 -Wl,-Bstatic -lXext -Wl,-Bdynamic
/usr/bin/ld:
/usr/lib/gcc/x86_64-linux-gnu/4.5.2/../../../../lib/libboost_thread-mt.a(thread.o):
undefined reference to symbol 'pthread_getspecific@@GLIBC_2.2.5'
/usr/bin/ld: note: 'pthread_getspecific@@GLIBC_2.2.5' is defined in DSO
/lib64/libpthread.so.0 so try adding it to the linker command line
/lib64/libpthread.so.0: could not read symbols: Invalid operation
collect2: ld returned 1 exit status

The link command actually lacks -pthread (no idea why this causes only a 
problem
with the static boost library):

/usr/bin/c++   -frounding-math -g
CMakeFiles/Alpha_shapes_2.dir/Alpha_shapes_2.o
CMakeFiles/Alpha_shapes_2.dir/qrc_Alpha_shapes_2.o  -o Alpha_shapes_2 
-rdynamic
-Wl,-Bstatic -lCGAL_Qt4 -lCGAL -lgmpxx -lmpfr -lgmp -lboost_thread-mt
-Wl,-Bdynamic -lQtOpenGL -lQtGui -lQtCore -Wl,-Bstatic -lGLU  -Wl,-Bdynamic 
-lGL
-lX11 -Wl,-Bstatic -lXext -Wl,-Bdynamic -pthread

Unfortunately, this command eliminates only a few dependencies. Most of the
remaining ones are probably caused by Qt. Maybe you are luckier if you happen 
to
have static libraries for Qt.

Joachim