Just like the Ron king's book "calling c from IDL ",In chapter 7,it talks about how to pass stuctures between IDL and c++. Now I need to get a structure created in c++ files. I followed the third example in that book.And I use the exactly the same name as it with the sufix ".c".But the compiler says there are about 12 errors. Is there any wrong with this example ! Is there anyone succeed. then I use the suffix ".cpp" ,then the compiler give no error. but when I test the function declared in the dlm file. IDL message out as follows: % Loaded DLM: TESTSTRUCT. % Dynamically loadable module TESTSTRUCT failed to define routine: TESTSTRUCTURE. % Execution halted at: $MAIN$ Thank you if you have any tips for me!