How to link libraries properly in synchronised sysroot on host computer

Ketank16 · wrote on 7 Nov 2019, 15:29

Hi, I'm trying to dig deeper into the fact that Qt by default doesn't want to compile with EGLFS on Beaglebone black. I've compiled some information regarding the errors shown in Qt's configuration step before cross compilation so if anyone who knows better than me in linking libraries, help me.

So, on the beaglebone itself, I've downloaded all the libraries necessary for EGLFS support (i.e. mesa. I searched initially for all the libraries with apt search libegl)

debian1@beaglebone:/usr/lib/arm-linux-gnueabihf$ ldd libEGL.so 
        linux-vdso.so.1 (0xbefd9000)
        libm.so.6 => /lib/arm-linux-gnueabihf/libm.so.6 (0xb6e80000)
        libGLdispatch.so.0 => /usr/lib/arm-linux-gnueabihf/libGLdispatch.so.0 (0xb6e02000)
        libdl.so.2 => /lib/arm-linux-gnueabihf/libdl.so.2 (0xb6def000)
        libpthread.so.0 => /lib/arm-linux-gnueabihf/libpthread.so.0 (0xb6dcb000)
        libc.so.6 => /lib/arm-linux-gnueabihf/libc.so.6 (0xb6cdd000)
        /lib/ld-linux-armhf.so.3 (0xb6f35000)

debian1@beaglebone:/usr/lib/arm-linux-gnueabihf$ ldd libGL.so
        linux-vdso.so.1 (0xbec53000)
        libGLX.so.0 => /usr/lib/arm-linux-gnueabihf/libGLX.so.0 (0xb6ee6000)
        libGLdispatch.so.0 => /usr/lib/arm-linux-gnueabihf/libGLdispatch.so.0 (0xb6e68000)
        libdl.so.2 => /lib/arm-linux-gnueabihf/libdl.so.2 (0xb6e55000)
        libpthread.so.0 => /lib/arm-linux-gnueabihf/libpthread.so.0 (0xb6e31000)
        libc.so.6 => /lib/arm-linux-gnueabihf/libc.so.6 (0xb6d43000)
        /lib/ld-linux-armhf.so.3 (0xb6fa1000)
        libX11.so.6 => /usr/lib/arm-linux-gnueabihf/libX11.so.6 (0xb6c4f000)
        libXext.so.6 => /usr/lib/arm-linux-gnueabihf/libXext.so.6 (0xb6c34000)
        libxcb.so.1 => /usr/lib/arm-linux-gnueabihf/libxcb.so.1 (0xb6c0c000)
        libXau.so.6 => /usr/lib/arm-linux-gnueabihf/libXau.so.6 (0xb6fbb000)
        libXdmcp.so.6 => /usr/lib/arm-linux-gnueabihf/libXdmcp.so.6 (0xb6bf8000)
        libbsd.so.0 => /lib/arm-linux-gnueabihf/libbsd.so.0 (0xb6bd5000)

debian1@beaglebone:/usr/lib/arm-linux-gnueabihf$ ldd libGLESv2.so 
        linux-vdso.so.1 (0xbeed6000)
        libGLdispatch.so.0 => /usr/lib/arm-linux-gnueabihf/libGLdispatch.so.0 (0xb6ede000)
        libc.so.6 => /lib/arm-linux-gnueabihf/libc.so.6 (0xb6df0000)
        /lib/ld-linux-armhf.so.3 (0xb6f9b000)
        libdl.so.2 => /lib/arm-linux-gnueabihf/libdl.so.2 (0xb6ddd000)

So, as you can see from the examples above, the libraries are linked and they are present in their respective folders. Then I sync the sysroot using rsync -avz to my computer and try to configure the Qt 5.13.2 from source files.

Here interstingly, I get the warnings where it cannot find the linked libraries.

/home/ketan/BBB/gcc/bin/../lib/gcc/arm-linux-gnueabihf/6.3.1/../../../../arm-linux-gnueabihf/bin/ld: warning: libGLdispatch.so.0, needed by /home/ketan/BBB/sysroot/usr/lib/arm-linux-gnueabihf/libGLESv2.so, not found (try using -rpath or -rpath-link)

or

/home/ketan/BBB/gcc/bin/../lib/gcc/arm-linux-gnueabihf/6.3.1/../../../../arm-linux-gnueabihf/bin/ld: warning: libGLX.so.0, needed by /home/ketan/BBB/sysroot/usr/lib/arm-linux-gnueabihf/libGL.so, not found (try using -rpath or -rpath-link)
/home/ketan/BBB/gcc/bin/../lib/gcc/arm-linux-gnueabihf/6.3.1/../../../../arm-linux-gnueabihf/bin/ld: warning: libGLdispatch.so.0, needed by /home/ketan/BBB/sysroot/usr/lib/arm-linux-gnueabihf/libGL.so, not found (try using -rpath or -rpath-link)

These are the EGL & OpenGL related lines in my qmake.conf:

QMAKE_INCDIR_EGL        = $$[QT_SYSROOT]/usr/include/EGL/
QMAKE_LIBDIR_EGL        = $$[QT_SYSROOT]/usr/lib/arm-linux-gnueabihf/
QMAKE_INCDIR_OPENGL_ES2 = $$[QT_SYSROOT]/usr/include/GLES2/
QMAKE_LIBDIR_OPENGL_ES2 = $$[QT_SYSROOT]/usr/lib/arm-linux-gnueabihf/
QMAKE_INCDIR_OPENVG     = $${QMAKE_INCDIR_EGL}
QMAKE_LIBDIR_OPENVG     = $${QMAKE_LIBDIR_EGL}

I can provide additional information if anyone wants.