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@@ -59,6 +59,18 @@ to wrap the given PtrData object which is, for example, created by DL::malloc().
DL::malloc() is a function to allocate a memory by using the C library function
malloc().
+We can define a callback using the module function "callback" as follows:
+
+ module Foo
+ extend DL::Importable
+ def my_comp(str1,str2)
+ str1 <=> str2
+ end
+ COMPARE = callback "int my_comp(char*,char*)"
+ end
+
+where Foo::COMPARE is a Symbol object which invokes the method "my_comp".
+
DL::Importable module is very useful. However, we sometimes encounter a case
that we must directly use low-level functions such as dlsym(). In such case,
we would use DL module functions. They are described in next section.