Les kirjoitti viestissään (lähetysaika tiistai 19 kesäkuu 2007): > So just to prove that this didn't change anything I tried: > gcc -L X11 GuiExample.cpp The option is "-lX11", not "-L X11". Linux is case sensitive and spaces are also significant. > I am sorry, and this is probably clear to some of you, but I > am at a loss to understand why this doesn't work. If I use > gcc, the presence or absence of a library .a or .so shouldn't > matter since the compiler should create the link chain based > on the extern definition, which could be resolved at load > time. The extern definition doesn't tell which library contains the symbol, just the function prototype or variable declaration. _You_ must tell the compiler which libraries to link in order to resolve the references. -- Markku Kolkka markku.kolkka@xxxxxx