gcc undefined reference even though ld finds the library and it contains the desired function

I work on a number of projects for which I must cross compile a number of libraries, some internal, some not. When working on a cross compiled application for one of our systems, I had to import some cross compiled internal libraries for my application. I'm using autotools for the application within Eclipse. The problem happens regardless of whether I'm in Eclipse or not. It happens regardless of platform for which I'm compiling, so all of my various versions of gcc encounter the same linking error. When I compile the application, the individual modules (*.c) compile fine, but when the final gcc command is issued to link everything into the final program, I get an 'undefined reference to GetCanMpdConfig' error.

Now, here's the kicker: the linker actually finds the file (I've verified this with -Wl,--verbose to get gcc to print the linker script). I direct your attention specifically to the line regarding -lcanmpdconf :

Making clean in src make[1]: Entering directory `/home/amarshall3/workspace/can_mpd/src' test -z "can_mpd" || rm -f can_mpd rm -f *.o make[1]: Leaving directory `/home/amarshall3/workspace/can_mpd/src' make[1]: Entering directory `/home/amarshall3/workspace/can_mpd' make[1]: Nothing to be done for `clean-am'. make[1]: Leaving directory `/home/amarshall3/workspace/can_mpd' Making all in src make[1]: Entering directory `/home/amarshall3/workspace/can_mpd/src' i686-linux-gnu-g++ -DPACKAGE_NAME=\"can_mpd\" -DPACKAGE_TARNAME=\"can_mpd\" -DPACKAGE_VERSION=\"1.13\" -DPACKAGE_STRING=\"can_mpd\ 1.13\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE_URL=\"\" -DPLATFORM=generic_x86 -I. -DBUILDSTAMP="\"`date '+%F %T'`\"" -I../dependencies/canmpdconf/1.0/generic_x86/include -I../dependencies/mow2monitor/1.0/generic_x86/include -DGENERIC_X86 -g -ggdb -O0 -Wall -Wl,--verbose -MT can_mpd-can_mpd.o -MD -MP -MF .deps/can_mpd-can_mpd.Tpo -c -o can_mpd-can_mpd.o `test -f 'can_mpd.cpp' || echo './'`can_mpd.cpp mv -f .deps/can_mpd-can_mpd.Tpo .deps/can_mpd-can_mpd.Po i686-linux-gnu-g++ -DPACKAGE_NAME=\"can_mpd\" -DPACKAGE_TARNAME=\"can_mpd\" -DPACKAGE_VERSION=\"1.13\" -DPACKAGE_STRING=\"can_mpd\ 1.13\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE_URL=\"\" -DPLATFORM=generic_x86 -I. -DBUILDSTAMP="\"`date '+%F %T'`\"" -I../dependencies/canmpdconf/1.0/generic_x86/include -I../dependencies/mow2monitor/1.0/generic_x86/include -DGENERIC_X86 -g -ggdb -O0 -Wall -Wl,--verbose -MT can_mpd-mpd_can.o -MD -MP -MF .deps/can_mpd-mpd_can.Tpo -c -o can_mpd-mpd_can.o `test -f 'mpd_can.cpp' || echo './'`mpd_can.cpp mv -f .deps/can_mpd-mpd_can.Tpo .deps/can_mpd-mpd_can.Po i686-linux-gnu-g++ -DPACKAGE_NAME=\"can_mpd\" -DPACKAGE_TARNAME=\"can_mpd\" -DPACKAGE_VERSION=\"1.13\" -DPACKAGE_STRING=\"can_mpd\ 1.13\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE_URL=\"\" -DPLATFORM=generic_x86 -I. -DBUILDSTAMP="\"`date '+%F %T'`\"" -I../dependencies/canmpdconf/1.0/generic_x86/include -I../dependencies/mow2monitor/1.0/generic_x86/include -DGENERIC_X86 -g -ggdb -O0 -Wall -Wl,--verbose -MT can_mpd-mpd_multiplexing.o -MD -MP -MF .deps/can_mpd-mpd_multiplexing.Tpo -c -o can_mpd-mpd_multiplexing.o `test -f 'mpd_multiplexing.cpp' || echo './'`mpd_multiplexing.cpp mv -f .deps/can_mpd-mpd_multiplexing.Tpo .deps/can_mpd-mpd_multiplexing.Po i686-linux-gnu-g++ -DPACKAGE_NAME=\"can_mpd\" -DPACKAGE_TARNAME=\"can_mpd\" -DPACKAGE_VERSION=\"1.13\" -DPACKAGE_STRING=\"can_mpd\ 1.13\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE_URL=\"\" -DPLATFORM=generic_x86 -I. -DBUILDSTAMP="\"`date '+%F %T'`\"" -I../dependencies/canmpdconf/1.0/generic_x86/include -I../dependencies/mow2monitor/1.0/generic_x86/include -DGENERIC_X86 -g -ggdb -O0 -Wall -Wl,--verbose -MT can_mpd-serial_can_provider.o -MD -MP -MF .deps/can_mpd-serial_can_provider.Tpo -c -o can_mpd-serial_can_provider.o `test -f 'provider/serial_can_provider.cpp' || echo './'`provider/serial_can_provider.cpp mv -f .deps/can_mpd-serial_can_provider.Tpo .deps/can_mpd-serial_can_provider.Po i686-linux-gnu-g++ -DPACKAGE_NAME=\"can_mpd\" -DPACKAGE_TARNAME=\"can_mpd\" -DPACKAGE_VERSION=\"1.13\" -DPACKAGE_STRING=\"can_mpd\ 1.13\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE_URL=\"\" -DPLATFORM=generic_x86 -I. -DBUILDSTAMP="\"`date '+%F %T'`\"" -I../dependencies/canmpdconf/1.0/generic_x86/include -I../dependencies/mow2monitor/1.0/generic_x86/include -DGENERIC_X86 -g -ggdb -O0 -Wall -Wl,--verbose -MT can_mpd-komodo_can_provider.o -MD -MP -MF .deps/can_mpd-komodo_can_provider.Tpo -c -o can_mpd-komodo_can_provider.o `test -f 'provider/komodo_can_provider.cpp' || echo './'`provider/komodo_can_provider.cpp mv -f .deps/can_mpd-komodo_can_provider.Tpo .deps/can_mpd-komodo_can_provider.Po i686-linux-gnu-gcc -DPACKAGE_NAME=\"can_mpd\" -DPACKAGE_TARNAME=\"can_mpd\" -DPACKAGE_VERSION=\"1.13\" -DPACKAGE_STRING=\"can_mpd\ 1.13\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE_URL=\"\" -DPLATFORM=generic_x86 -I. -g -O2 -MT komodo.o -MD -MP -MF .deps/komodo.Tpo -c -o komodo.o `test -f 'can/komodo/komodo.c' || echo './'`can/komodo/komodo.c mv -f .deps/komodo.Tpo .deps/komodo.Po i686-linux-gnu-g++ -DBUILDSTAMP="\"`date '+%F %T'`\"" -I../dependencies/canmpdconf/1.0/generic_x86/include -I../dependencies/mow2monitor/1.0/generic_x86/include -DGENERIC_X86 -g -ggdb -O0 -Wall -Wl,--verbose -L../dependencies/canmpdconf/1.0/generic_x86/lib -L../dependencies/mow2monitor/1.0/generic_x86/lib -Wl,--verbose -o can_mpd can_mpd-can_mpd.o can_mpd-mpd_can.o can_mpd-mpd_multiplexing.o can_mpd-serial_can_provider.o can_mpd-komodo_can_provider.o komodo.o -lcanmpdconf -lmow2monitor -lpthread -ldl GNU ld (GNU Binutils for Ubuntu) 2.23.52.20130913 Supported emulations: elf_i386 i386linux elf32_x86_64 elf_x86_64 elf_l1om elf_k1om i386pep i386pe GNU ld (GNU Binutils for Ubuntu) 2.23.52.20130913 Supported emulations: elf_i386 i386linux elf32_x86_64 elf_x86_64 elf_l1om elf_k1om i386pep i386pe using internal linker script: ================================================== /* Script for -z combreloc: combine and sort reloc 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{ *(.debug_ranges) } /* DWARF Extension. */ .debug_macro 0 : { *(.debug_macro) } .gnu.attributes 0 : { KEEP (*(.gnu.attributes)) } /DISCARD/ : { *(.note.GNU-stack) *(.gnu_debuglink) *(.gnu.lto_*) } } ================================================== attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/crt1.o succeeded /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/crt1.o attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/crti.o succeeded /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/crti.o attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/crtbegin.o succeeded /usr/lib/gcc/i686-linux-gnu/4.8/crtbegin.o attempt to open can_mpd-can_mpd.o succeeded can_mpd-can_mpd.o attempt to open can_mpd-mpd_can.o succeeded can_mpd-mpd_can.o attempt to open can_mpd-mpd_multiplexing.o succeeded can_mpd-mpd_multiplexing.o attempt to open can_mpd-serial_can_provider.o succeeded can_mpd-serial_can_provider.o attempt to open can_mpd-komodo_can_provider.o succeeded can_mpd-komodo_can_provider.o attempt to open komodo.o succeeded komodo.o attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libcanmpdconf.so succeeded -lcanmpdconf (../dependencies/canmpdconf/1.0/generic_x86/lib/libcanmpdconf.so) attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libmow2monitor.so failed attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libmow2monitor.a failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libmow2monitor.so succeeded -lmow2monitor (../dependencies/mow2monitor/1.0/generic_x86/lib/libmow2monitor.so) attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libpthread.so failed attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libpthread.a failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libpthread.so failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libpthread.a failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/libpthread.so failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/libpthread.a failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/libpthread.so succeeded opened script file /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/libpthread.so opened script file /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/libpthread.so attempt to open /lib/i386-linux-gnu/libpthread.so.0 succeeded /lib/i386-linux-gnu/libpthread.so.0 attempt to open /usr/lib/i386-linux-gnu/libpthread_nonshared.a succeeded attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libdl.so failed attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libdl.a failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libdl.so failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libdl.a failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/libdl.so failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/libdl.a failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/libdl.so succeeded -ldl (/usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/libdl.so) attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libstdc++.so failed attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libstdc++.a failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libstdc++.so failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libstdc++.a failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/libstdc++.so succeeded -lstdc++ (/usr/lib/gcc/i686-linux-gnu/4.8/libstdc++.so) attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libm.so failed attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libm.a failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libm.so failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libm.a failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/libm.so failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/libm.a failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/libm.so succeeded -lm (/usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/libm.so) attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libgcc_s.so failed attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libgcc_s.a failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libgcc_s.so failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libgcc_s.a failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/libgcc_s.so succeeded -lgcc_s (/usr/lib/gcc/i686-linux-gnu/4.8/libgcc_s.so) attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libgcc.so failed attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libgcc.a failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libgcc.so failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libgcc.a failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/libgcc.so failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/libgcc.a succeeded attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libc.so failed attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libc.a failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libc.so failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libc.a failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/libc.so failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/libc.a failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/libc.so succeeded opened script file /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/libc.so opened script file /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/libc.so attempt to open /lib/i386-linux-gnu/libc.so.6 succeeded /lib/i386-linux-gnu/libc.so.6 attempt to open /usr/lib/i386-linux-gnu/libc_nonshared.a succeeded (/usr/lib/i386-linux-gnu/libc_nonshared.a)elf-init.oS (/usr/lib/i386-linux-gnu/libc_nonshared.a)atexit.oS attempt to open /lib/i386-linux-gnu/ld-linux.so.2 succeeded /lib/i386-linux-gnu/ld-linux.so.2 attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libgcc_s.so failed attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libgcc_s.a failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libgcc_s.so failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libgcc_s.a failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/libgcc_s.so succeeded -lgcc_s (/usr/lib/gcc/i686-linux-gnu/4.8/libgcc_s.so) attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libgcc.so failed attempt to open ../dependencies/canmpdconf/1.0/generic_x86/lib/libgcc.a failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libgcc.so failed attempt to open ../dependencies/mow2monitor/1.0/generic_x86/lib/libgcc.a failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/libgcc.so failed attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/libgcc.a succeeded attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/crtend.o succeeded /usr/lib/gcc/i686-linux-gnu/4.8/crtend.o attempt to open /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/crtn.o succeeded /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/crtn.o ld-linux.so.2 needed by /lib/i386-linux-gnu/libpthread.so.0 found ld-linux.so.2 at /lib/i386-linux-gnu/ld-linux.so.2 libm.so.6 needed by /usr/lib/gcc/i686-linux-gnu/4.8/libstdc++.so found libm.so at /usr/lib/gcc/i686-linux-gnu/4.8/../../../i386-linux-gnu/libm.so make[1]: Leaving directory `/home/amarshall3/workspace/can_mpd/src' can_mpd-can_mpd.o: In function `main': /home/amarshall3/workspace/can_mpd/src/can_mpd.cpp:180: undefined reference to `GetCanMpdConfig(CAN_MPD_CONFIG*, unsigned int*)' collect2: error: ld returned 1 exit status make[1]: *** [can_mpd] Error 1 make: *** [all-recursive] Error 1 

I have also verified that the library is for the correct platform (x86) and so therefore is in the correct format. I've also verified that it does indeed contain the required symbol (GetCanMpdConfig) with the output of nm:

0000305c B __bss_start 0000305c b completed.6608 w __cxa_finalize@@GLIBC_2.1.3 00000940 t deregister_tm_clones 000009d0 t __do_global_dtors_aux 00002e88 t __do_global_dtors_aux_fini_array_entry 00003058 d __dso_handle 00002ee4 d _DYNAMIC 0000305c D _edata 00003060 B _end U __errno_location@@GLIBC_2.0 00002ea0 d Errors U fclose@@GLIBC_2.1 U fgets@@GLIBC_2.0 00001184 T _fini U fopen@@GLIBC_2.1 U __fprintf_chk@@GLIBC_2.3.4 00000a20 t frame_dummy 00002e84 t __frame_dummy_init_array_entry 000014e8 r __FRAME_END__ 00000ef0 T GetCanMpdConfError 00000b60 T GetCanMpdConfig 00000a60 T GetCanMpdConfVersion U GetConfigFilePath 00003000 d _GLOBAL_OFFSET_TABLE_ w __gmon_start__ 00002ec0 d Handlers 000007c4 T _init w _ITM_deregisterTMCloneTable w _ITM_registerTMCloneTable 00002e8c d __JCR_END__ 00002e8c d __JCR_LIST__ w _Jv_RegisterClasses 00000f20 T read_provider_type 000010c0 T read_serial_baud 00001010 T read_serial_device 00000980 t register_tm_clones 00000a80 T SetCanMpdConfig U __stack_chk_fail@@GLIBC_2.4 00001170 t __stack_chk_fail_local U strchr@@GLIBC_2.0 U strlen@@GLIBC_2.0 U strncmp@@GLIBC_2.0 U strncpy@@GLIBC_2.0 U strtol@@GLIBC_2.0 0000305c d __TMC_END__ 00000f90 T write_provider_type 00001110 T write_serial_baud 00001060 T write_serial_device 00000930 t __x86.get_pc_thunk.bx 00000f18 t __x86.get_pc_thunk.cx U __xstat@@GLIBC_2.0 

To summarize: 1) Linking order in the gcc commands is correct (-llibname after -o blah.cpp) 2) Linker finds the library (libcanmpdconf.so) 3) Library is in the correct format for the platform (x86) 4) Library contains the symbol (see nm output)

There should be no reason, as far as I can tell, why there should be an undefined reference to any symbol that clearly exists in my library, which the linker can find. Does anybody know of any other ways I can try to troubleshoot this or what might be wrong ?