Question

My Mac OS X plugin includes some frameworks that use Qt. These frameworks create a UI that displays jpegs using Qt’s jpeg plugin dylib.

I use install_name_tool to set @rpath in my plugin so that it can be located anywhere. The host application finds and loads my frameworks fine, but the Qt jpeg plugin dylib won’t then load at runtime.

The Qt jpeg plugin’s id is:

@rpath/qt/plugins/imageformats/libqjpeg.dylib

Its dependent Qt shared library list is:

@rpath/QtGui.framework/Versions/4/QtGui
@rpath/QtCore.framework/Versions/4/QtCore

When I set QT_DEBUG_PLUGINS to 1, the output from Console is:

QFactoryLoader::QFactoryLoader() looking at "/Users/Robin/MyPlugin.plugin/Contents/Frameworks/qt/plugins/imageformats/libqjpeg.dylib" 
"Cannot load library /Users/Robin/MyPlugin.plugin/Contents/Frameworks/qt/plugins/imageformats/libqjpeg.dylib: " 
not a plugin`

If I replace @rpath in the list of dependent libraries with hardcoded locations, everything works fine, but my plugin can’t then be located anywhere.

This problem appears to be on Snow Leopard, but not Lion. I’m using Qt 4.6.3.

Any suggestions / advice appreciated on how I get libqjpeg loading successfully. Thanks.

Answer 1

I fixed this by adding an rpath path name to QtCore using install_name_tool:

install_name_tool -add_rpath @loader_path/../../.. QtCore.framework/Versions/4/QtCore