I'm trying to build ginac from source (master branch, commit a104ecb34a015fc40a4bdc16ae6ea038ecb8c55d). The configure step is unable to find libreadline for some reason and I can't figure out why. Here is what I've got: luke@ThinkPad-W510:~/repos/ginac(master)$ ll /usr/lib/libreadline*.* -rw-r--r-- 1 root root 505980 2011-09-01 10:43 /usr/lib/libreadline.a lrwxrwxrwx 1 root root 21 2011-09-01 10:43 /usr/lib/libreadline.so -> /lib/libreadline.so.6 luke@ThinkPad-W510:~/repos/ginac(master)$ ls /usr/include/readline/ chardefs.h history.h keymaps.h readline.h rlconf.h rlstdc.h rltypedefs.h tilde.h luke@ThinkPad-W510:~/repos/ginac(master)$ ./configure checking for a BSD-compatible install... /usr/bin/install -c checking whether build environment is sane... yes checking for a thread-safe mkdir -p... /bin/mkdir -p checking for gawk... gawk checking whether make sets $(MAKE)... yes checking for g++... g++ checking whether the C++ compiler works... yes checking for C++ compiler default output file name... a.out checking for suffix of executables... checking whether we are cross compiling... no checking for suffix of object files... o checking whether we are using the GNU C++ compiler... yes checking whether g++ accepts -g... yes checking for style of include used by make... GNU checking dependency style of g++... gcc3 checking how to run the C++ preprocessor... g++ -E checking build system type... x86_64-unknown-linux-gnu checking host system type... x86_64-unknown-linux-gnu checking how to print strings... printf checking for gcc... gcc checking whether we are using the GNU C compiler... yes checking whether gcc accepts -g... yes checking for gcc option to accept ISO C89... none needed checking dependency style of gcc... gcc3 checking for a sed that does not truncate output... /bin/sed checking for grep that handles long lines and -e... /bin/grep checking for egrep... /bin/grep -E checking for fgrep... /bin/grep -F checking for ld used by gcc... /usr/bin/ld checking if the linker (/usr/bin/ld) is GNU ld... yes checking for BSD- or MS-compatible name lister (nm)... /usr/bin/nm -B checking the name lister (/usr/bin/nm -B) interface... BSD nm checking whether ln -s works... yes checking the maximum length of command line arguments... 1572864 checking whether the shell understands some XSI constructs... yes checking whether the shell understands "+="... yes checking how to convert x86_64-unknown-linux-gnu file names to x86_64-unknown-linux-gnu format... func_convert_file_noop checking how to convert x86_64-unknown-linux-gnu file names to toolchain format... func_convert_file_noop checking for /usr/bin/ld option to reload object files... -r checking for objdump... objdump checking how to recognize dependent libraries... pass_all checking for dlltool... no checking how to associate runtime and link libraries... printf %s\n checking for ar... ar checking for archiver @FILE support... @ checking for strip... strip checking for ranlib... ranlib checking command to parse /usr/bin/nm -B output from gcc object... ok checking for sysroot... no checking for mt... mt checking if mt is a manifest tool... no checking how to run the C preprocessor... gcc -E checking for ANSI C header files... yes checking for sys/types.h... yes checking for sys/stat.h... yes checking for stdlib.h... yes checking for string.h... yes checking for memory.h... yes checking for strings.h... yes checking for inttypes.h... yes checking for stdint.h... yes checking for unistd.h... yes checking for dlfcn.h... yes checking for objdir... .libs checking if gcc supports -fno-rtti -fno-exceptions... no checking for gcc option to produce PIC... -fPIC -DPIC checking if gcc PIC flag -fPIC -DPIC works... yes checking if gcc static flag -static works... yes checking if gcc supports -c -o file.o... yes checking if gcc supports -c -o file.o... (cached) yes checking whether the gcc linker (/usr/bin/ld -m elf_x86_64) supports shared libraries... yes checking whether -lc should be explicitly linked in... no checking dynamic linker characteristics... GNU/Linux ld.so checking how to hardcode library paths into programs... immediate checking whether stripping libraries is possible... yes checking if libtool supports shared libraries... yes checking whether to build shared libraries... yes checking whether to build static libraries... yes checking how to run the C++ preprocessor... g++ -E checking for ld used by g++... /usr/bin/ld -m elf_x86_64 checking if the linker (/usr/bin/ld -m elf_x86_64) is GNU ld... yes checking whether the g++ linker (/usr/bin/ld -m elf_x86_64) supports shared libraries... yes checking for g++ option to produce PIC... -fPIC -DPIC checking if g++ PIC flag -fPIC -DPIC works... yes checking if g++ static flag -static works... yes checking if g++ supports -c -o file.o... yes checking if g++ supports -c -o file.o... (cached) yes checking whether the g++ linker (/usr/bin/ld -m elf_x86_64) supports shared libraries... yes checking dynamic linker characteristics... (cached) GNU/Linux ld.so checking how to hardcode library paths into programs... immediate checking for flex... flex checking lex output file root... lex.yy checking lex library... -lfl checking whether yytext is a pointer... yes checking for bison... bison -y checking for bison... /usr/bin/bison checking for standard C++ header files... yes checking for pkg-config... /usr/bin/pkg-config checking pkg-config is at least version 0.9.0... yes checking for CLN... yes checking for ld used by GCC... /usr/bin/ld -m elf_x86_64 checking if the linker (/usr/bin/ld -m elf_x86_64) is GNU ld... yes checking for shared library run path origin... done checking for long long... yes checking for unistd.h... (cached) yes checking whether struct rusage is declared in <sys/resource.h>... yes checking for tgetent... no checking for tgetent in -lncurses... no checking for tgetent in -ltermcap... no checking readline/readline.h usability... yes checking readline/readline.h presence... yes checking for readline/readline.h... yes checking readline/history.h usability... yes checking readline/history.h presence... yes checking for readline/history.h... yes checking for version of libreadline... yes checking for readline in -lreadline... no checking for dlfcn.h... (cached) yes checking for dlopen in -ldl... no checking for dlopen... no configure: WARNING: Could not found working dlopen(). GiNaC::compile_ex will be disabled. checking for doxygen... /home/luke/usr/bin/doxygen checking for latex... /home/luke/usr/texlive/2011/bin/x86_64-linux/latex checking for pdflatex... /home/luke/usr/texlive/2011/bin/x86_64-linux/pdflatex checking for makeindex... /home/luke/usr/texlive/2011/bin/x86_64-linux/makeindex checking for makeinfo... /usr/bin/makeinfo checking for dvips... /home/luke/usr/texlive/2011/bin/x86_64-linux/dvips checking for fig2dev... /usr/bin/fig2dev configure: creating ./config.status config.status: creating Makefile config.status: creating GiNaC.spec config.status: creating ginac.pc config.status: creating ginac/Makefile config.status: creating check/Makefile config.status: creating ginsh/Makefile config.status: creating ginsh/ginsh.1 config.status: creating tools/Makefile config.status: creating tools/viewgar.1 config.status: creating tools/ginac-excompiler config.status: creating doc/Makefile config.status: creating doc/examples/Makefile config.status: creating doc/tutorial/Makefile config.status: creating doc/reference/Makefile config.status: creating doc/reference/DoxyfileHTML config.status: creating doc/reference/DoxyfileTEX config.status: creating doc/reference/DoxyfilePDF config.status: creating doc/reference/Doxyfooter config.status: creating config/config.h config.status: config/config.h is unchanged config.status: creating ginac/version.h config.status: ginac/version.h is unchanged config.status: executing depfiles commands config.status: executing libtool commands === The following minor problems have been detected by configure. === Please check the messages below before running "make". === (see the section 'Common Problems' in the INSTALL file) == ginsh will not compile, because libreadline could not be found. Configuration of GiNaC 1.6.2 done. Now type "make". Any ideas why configure wouldn't be finding readline or how to go about solving this problem? Also, I don't understand why a working dlopen() was not found. I have /usr/include/dlfcn.h, and I have successfully compiled code that makes calls to dlopen() and friends. Thanks, ~Luke -- "Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety." -- Benjamin Franklin, Historical Review of Pennsylvania, 1759