问题
I am writing a plugin system which is separated other 3 modules:
- plugin_system.c - the core of the system
- list.c - contains a linked list implementation for plugins' storage
- plugin_interface.h - contains the declaration needed by plugins, has no source file associated with
plugin_interface.h only contains only of types and the function:
extern int plugin_register(PluginManager *plug_manager, const char *name, Plugin *plug);
which is defined in plugin_system.c
When loading a plugin, the plugin system look for a funcion init_plugname() and call it, that function must call plugin_register to register the plugin.
The program is compiled with complex recursive Makefiles (not the best idea), but what I try to achieve is:
I compile the plugin system object in the main program folder, it is then linked with the main program. From make execution:
gcc -Wall -O2 -std=gnu99 -D DEBUG -g -fPIC -c -o /home/kowa/code/reseaux/projet/ringo/c/bin/list.o list.c
gcc -Wall -O2 -std=gnu99 -D DEBUG -g -fPIC -c -o /home/kowa/code/reseaux/projet/ringo/c/bin/plugin_system.o plugin_system.c
A plugin is compiled with gcc -fPIC -c -o plugname.o plugname.c plug_system.o followed by gcc -o plugname.so plugname.o plug_system.o -shared
I try to load the plugin in my main program and get this error:
symbol lookup error: ./plugins/zyva.so: undefined symbol: exists
exists is a function in the list module used by the plugin_system module to store plugins, the plugin_register function mentionned aboved calls it.
I've never done that kind of system before and I'm not an expert in shared library, I guess the problem is from how I compile the whole project, I may miss some linkage...
回答1:
I just forgot to link the plugin with list.o which is used by the plugin_system.o...
来源：https://stackoverflow.com/questions/36797376/c-pluginsystem-symbol-lookup-error