39 lines
1.0 KiB
C
39 lines
1.0 KiB
C
// declare base_func; no mark -> load-time imported symbol
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void base_func(void);
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// setup plugin_func as a function pointer so that it can be linked at run time
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typedef void PLUGIN_Func(void);
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PLUGIN_Func *plugin_func = 0;
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// need to include for dlopen and dlsym
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#include <dlfcn.h>
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// helper macro for dlsym that handles the casting of function pointers
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#define GET_PROC(var,mod,name) *((void**)(&(var))) = dlsym((mod),(name))
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int main(){
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// functions linked by load-time linking can be called directly without further setup
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base_func();
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// to call a function with run-time linking, we must manually load and link it
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void *module = dlopen("$ORIGIN/linux_plugin.so", RTLD_NOW);
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if (module != 0){
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GET_PROC(plugin_func, module, "plugin_func");
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}
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// calls to plugin_func only work after the "plugin" loaded successfully
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if (plugin_func != 0){
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plugin_func();
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}
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// demonstration: the data structures contained in the 'base' are not duplicated in each binary
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base_func();
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}
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