Takaaki Tateishi
12/9/2004 2:45:00 PM
Guillaume Marcais wrote:
> How can I call a pointer to a function. Let say:
>
> <code>
> int my_function(void);
> int (*function_hook)(void);
> function_hook = my_function;
> </code>
If the function_hook is globally defined variable, I mean it should be
exported, the address
of function_hook is obtained as follows.
module MyLib
extend DL::Importable
dlload "foo.so"
HOOK_ADDR = symbol "function_hook"
end
and use Symbol.new to construct function call as follows:
def call_function_hook()
sym = DL::Symbol.new(MyLib::HOOK_ADDR.ptr, "function_hook", "I")
result = sym.call
return result[0]
end
the following foo.c and foo.rb are samples..
foo.c --
int my_function(){
return 20;
}
int (*function_hook)();
void define_hook(){
function_hook = &my_function;
}
foo.rb --
require 'dl/import'
module MyLib
extend DL::Importable
dlload "foo.so"
extern "void define_hook()"
HOOK_ADDR = symbol "function_hook"
def call_function_hook()
sym = DL::Symbol.new(HOOK_ADDR.ptr, "function_hook", "I")
result = sym.call
result[0]
end
module_function :call_function_hook
end
#MyLib.define_hook()
p MyLib.call_function_hook()
--
Takaaki Tateishi <ttate@ttsky.net>