Debugging a so library loaded with dlopen()?

Question

C++ / C#

CentOS 6.2, Qt Creator IDE 2.4.1 (using GNU toolchain).
I decided to attach a trivial plugin system to my fastcgi server. Plugins are loaded from the plugins/ directory using library functions like dlopen().
How to debug a plugin? I put a breakpoint, I start the server in debugging - the point is ignored. gdb problems? Problems with my hands or interaural ganglion?
So far, I'm guessing the following ways:
> maybe I don't provide debug information, so gdb doesn't care
> log the old fashioned way
> don't use the current IDE (gdb often falls off there)
Thanks in advance for adequate answers to a possibly stupid question.

Answer 1

Check directly in gdb to rule out IDE issues.

Answer 2

1. Without debugging information, the IDE simply cannot link the execution point to the sources, i.e. You can't trace the program visually. Debugging info should be added.
2. Try setting a breakpoint after the plugin's dlopen(), and then setting a breakpoint on a function in the plugin. Since before dlopen () gdb simply will not see the symbols that are loaded by the plugin.

Answer 3

I'm not exactly sure, but after dlopen I can see how the dll is mapped into memory, and load debugging information, something like this: sourceware.org/glibc/wiki/Debugging/Loader_Debugging
Start reading approximately from info proc mapping.
BUT! I'm pretty sure that this won't be the optimal way, and it can be done in an easier way.