Re: Link fails on Ubuntu 16.04 (on WSL) due to undefined reference to symbol 'FcUcs4ToUtf8'

[Ethan M. <merritt@u.washington.edu>]

Never mind.  I see I have horribly mangled the configure call to
AC_SEARCH_LIBS.  I'll try to fix it.   As I said before, I am not
very good at modifying the autoconf scripts.

Please try again with the repaired configure.ac

  sorry for the mess

	Ethan


On Saturday, 10 March 2018 22:40:43 sfeam via gnuplot-beta wrote:
> On Sunday, 11 March 2018 14:04:19 Tatsuro MATSUOKA wrote:
> > Sorry I forgot to reply to beta-list
> > 
> > ----- Original Message -----
> > 
> > > From: Dima Kogan
> > > To: gnuplot-beta
> > > Cc: 
> > > Date: 2018/3/11, Sun 10:55
> > > Subject: Re: Link fails on Ubuntu 16.04 (on WSL) due to undefined reference to symbol 'FcUcs4ToUtf8'
> > > 
> > >T atsuro MATSUOKA <tma...@ya...> writes:
> > > 
> > >>  I pull the recent git repository and tried to build on Ubuntu 16.04 on
> > >>  WSL.
> > >> 
> > >>  In linking gnuplot executable I see
> > >> 
> > >>  undefined reference to symbol 'FcUcs4ToUtf8'
> > > 
> > > You're either not linking with the libfontconfig library, or you have
> > > the wrong library, or something. Send over the full build log if you
> > > want help debugging.
> > > 
> > > ------------------------------------------------------------------------------
> > > Check out the vibrant tech community on one of the world's most
> > > engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> > 
> > 
> > You are right. In link stage, -lfontconfig is missing.
> > 
> > c++ 
> >  -g -O2 -I/usr/lib/x86_64-linux-gnu/wx/include/gtk2-unicode-3.0 
> > -I/usr/include/wx-3.0 -D_FILE_OFFSET_BITS=64 -DWXUSINGDLL -D__WXGTK__ 
> > -pthread -I/opt/fontconfig-2.12.93/include -I/usr/include/pango-1.0 
> > -I/usr/include/harfbuzz -I/usr/include/pango-1.0 -I/usr/include/cairo 
> > -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include 
> > -I/usr/include/pixman-1 -I/usr/include/uuid -I/usr/include/freetype2 
> > -I/usr/include/libpng12 -DWXT_MONOTHREADED -fPIC   -lcerf  -o gnuplot 
> > alloc.o axis.o breaders.o boundary.o color.o command.o contour.o 
> > datablock.o datafile.o dynarray.o eval.o external.o fit.o gadgets.o 
> > getcolor.o graph3d.o graphics.o help.o hidden3d.o history.o internal.o 
> > interpol.o jitter.o libcerf.o matrix.o misc.o mouse.o multiplot.o 
> > parse.o plot.o plot2d.o plot3d.o pm3d.o readline.o save.o scanner.o 
> > set.o show.o specfun.o standard.o stats.o stdfn.o tables.o tabulate.o 
> > term.o time.o unset.o util.o util3d.o variable.o version.o
> > wxterminal/wxt_gui.o wxterminal/gp_cairo.o 
> > wxterminal/gp_cairo_helpers.o  qtterminal/qt_term.o -lreadline  
> > -lncurses  -lz -lgd -lgd -llua5.3 -lcaca  -L/usr/lib/x86_64-linux-gnu 
> > -pthread   -lwx_gtk2u_xrc-3.0 -lwx_gtk2u_html-3.0 -lwx_gtk2u_qa-3.0 
> > -lwx_gtk2u_adv-3.0 -lwx_gtk2u_core-3.0 -lwx_baseu_xml-3.0 
> > -lwx_baseu_net-3.0 -lwx_baseu-3.0  -lpangocairo-1.0 -lpango-1.0 
> > -lgobject-2.0 -lglib-2.0 -lcairo  -lX11  -lQt5Network -lQt5Svg 
> > -lQt5PrintSupport -lQt5Widgets -lQt5Gui -lQt5Core -lcaca -ldl -lm 
> > -lcerf  -lz -lpangocairo-1.0 -lpango-1.0 -lgobject-2.0 -lcairo 
> > -lglib-2.0
> > 
> > Adding manually -lfontcondig to the above, link is successful.
> > 
> > Compressed config.log.bz2 is attached.
> > 
> > Workaround is to add LIBS='-lfontconfig' to configure flag.
> 
> 
> I do not understand why the configure script is not doing that
> already.  It tests for the library using this command:
> 
>   AC_SEARCH_LIBS(foo, fontconfig, ,
>   AC_DEFINE(HAVE_LIBFONTCONFIG,1,[ used for unicode codepoint->utf8 conversion ]),,)
> 
> The documentation for AC_SEARCH_LIBS says that it will
> 
>   Search for a library defining function if it's not already available.
>   [...]
>   Prepend -llibrary to LIBS for the first library found to contain function,
>   and run action-if-found. If the function is not found, run action-if-not-found.
> 
> It must have found the function (since your code is trying to use it
> inside a conditional for HAVE_LIBFONTCONFIG), so it should have added
> -lfontconfig to the definition of LIBS.   Why did it not?
> 
> But also I do not understand for a second reason.
> As you say, libfontconfig is already used by various support libraries
> that gnuplot already uses  (cairo pango-ft gdlib qt ...).
> So it must surely be linked in already because of the library dependencies
> for various terminals.  I wonder that is not true on your machine.
> 
> When I run ./configure it adds -lfontconfig to both TERM_LIBS
> and GTK_LIBS.  Does this not happen on your setup?
> 
> I am not very good at using or modifying the autoconf tools.
> I hope someone else can help explain or fix this.
> 
> 	Ethan
> 
>  
> 
> > 
> > 
> > I think that gnuplot so far uses fontconfig via external libraries (e.g. cairo, pango).
> > Is this Commit [7ecbe3] first event to use fontconfig directory.
> > Gnuplot check libfontconfig add -lfontconfig in library flag.
> > 
> > Tatsuro
> > 
> > 
> > If it is in the case, libconfig
> > 
> > Tatsuro
> 
> 
> ------------------------------------------------------------------------------
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> _______________________________________________
> gnuplot-beta mailing list
> gnu...@li...
> Membership management via: https://lists.sourceforge.net/lists/listinfo/gnuplot-beta

-- 
Ethan A Merritt, Dept of Biochemistry
Biomolecular Structure Center,  K-428 Health Sciences Bldg
MS 357742,   University of Washington, Seattle 98195-7742