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Question

During a cross-compilation I got this linker error:

/home/tech/opt/gcc-4.7-linaro-rpi-gnueabihf/bin/../lib/gcc/arm-linux-gnueabihf/4.7.2/../../../../arm-linux-gnueabihf/bin/ld: cannot find -lfontconfig

This is the g++ command line:

/home/tech/opt/gcc-4.7-linaro-rpi-gnueabihf/bin/arm-linux-gnueabihf-g++ -Wl,-rpath-link,/mnt/rasp-pi-rootfs/opt/vc/lib -Wl,-rpath-link,/mnt/rasp-pi-rootfs/usr/lib/arm-linux-gnueabihf -Wl,-rpath-link,/mnt/rasp-pi-rootfs/lib/arm-linux-gnueabihf -mfloat-abi=hard --sysroot=/mnt/rasp-pi-rootfs -Wl,-O1 -o fontconfig fontconfig.o   --sysroot=/mnt/rasp-pi-rootfs -lpthread -L/mnt/rasp-pi-rootfs/usr/lib/arm-linux-gnueabihf/ -lfreetype -lfontconfig 

And

ls /mnt/rasp-pi-rootfs/usr/lib/arm-linux-gnueabihf/libfontconfig*

/mnt/rasp-pi-rootfs/usr/lib/arm-linux-gnueabihf/libfontconfig.so.1
/mnt/rasp-pi-rootfs/usr/lib/arm-linux-gnueabihf/libfontconfig.so.1.8.0

I don't understand "why" the linker cannot find that library. What do you suggest to do in such a case to investigate further?

Answer 1

Linker requires import library with .a extension of the library for linker operations because it contains the signatures of classes and functions needed by the linker for linking while .so libraries are shared objects used at runtime.

You need to find the directory where you have libfontconfig.a (eg: through the command locate libfontconfig.a or 'find / -name libfontconfig.a') and then add it to the command line with -L/path/of/directory.