Mysql plugin not loaded when running in debug mode

  • Hi there.

    Using QtSDK 1.2.1 on a mac.

    I'm trying to identify an issue with my application, and as such trying to use Qt debug libraries.
    Following the documentation there:
    I set export DYLD_IMAGE_SUFFIX=_debug

    When doing so, I can see that the Qt debut libraries are properly loaded.
    However, it can't find the mysql plugins.

    mysql plugin is installed, for both standard and debug:
    jyaimac:plugins jyavenard$ ls -l sqldrivers/
    total 4976
    -rwxr-xr-x 1 jyavenard staff 646992 20 Apr 13:39 libqsqlite.dylib
    -rwxr-xr-x 1 jyavenard staff 958048 20 Apr 13:39 libqsqlite_debug.dylib
    -rwxr-xr-x 1 jyavenard staff 93376 20 Apr 15:02 libqsqlmysql.dylib
    -rwxr-xr-x 1 jyavenard staff 187752 20 Apr 15:01 libqsqlmysql_debug.dylib
    -rwxr-xr-x 1 jyavenard staff 169032 20 Apr 13:39 libqsqlodbc.dylib
    -rwxr-xr-x 1 jyavenard staff 210144 20 Apr 13:39 libqsqlodbc_debug.dylib
    -rwxr-xr-x 1 jyavenard staff 111176 20 Apr 13:39 libqsqlpsql.dylib
    -rwxr-xr-x 1 jyavenard staff 159088 20 Apr 13:39 libqsqlpsql_debug.dylib

    If I unset DYLD_IMAGE_SUFFIX, then everything works fine...

    What is the proper way of not only running debug version of Qt and still have access to plugins ?

    Thanks in advance.

  • I would suspect that the dynamic linker tries to load libmysqlclient_debug.dylib - i.e. the mysql library itself with the respective suffix. Try to find the installation directory of your mysql libs:


    on the shell issue

    locate libmysqlclient.dylib

    and then setup some symlinks:

    cd /usr/local/mysql/lib
    ln -s libmysqlclient.dylib libmysqlclient_debug.dylib

    You might need to add the respective symlinks for the versioned file names too.

  • Actuelly, i had already created the symlinks as I too thought it was the issue.

    However, activating linker logs showed that it was not even loading the original plugin to start with.

    I then looked at what QStringList QCoreApplication::libraryPaths would return, and the value was different to when running in non-debug mode.
    In non-debug it points to the Qt system plugin directory (where the MySQL plugin was copied) but when running in debug mode it is set to the working dir.

    So I simply created a link in my working directory to the system Qt lib. And it's now working.

    A tad confusing...
    Since I've found why it's crashing, and the bug is in qt unfortunately.

    Thanks for the help.

Log in to reply

Looks like your connection to Qt Forum was lost, please wait while we try to reconnect.