Can't use parameter reference from DLL C on pl/sql

Question

hi all, I have dll(newStr.dll) write by c language with a function name is "strNew", following code in c and pl/sql:
char* strNew(char *& str){
     if (str != NULL){
          str = strdup("");
          str = strcat(str,"String is not null.");     
     }else{
          str = strdup("");
          str = strcat(str,"String is null.");     
     return str;
On PL/SQL I call the dll(newStr.dll), following code on pl/sql:
1) Create library:
     CREATE OR REPLACE LIBRARY TestDLL AS 'D:\newStr.dll';
2) Create package:
     CREATE OR REPLACE
     PACKAGE TEST_DLL AS
     FUNCTION strNew(str IN OUT varchar2) RETURN VARCHAR2;
     END TEST_DLL
     CREATE OR REPLACE
     PACKAGE BODY TEST_DLL AS
     FUNCTION strNew(str IN OUT VARCHAR2)
     RETURN VARCHAR2 AS
     EXTERNAL LIBRARY TestDLL
     NAME "strNew"
     LANGUAGE C
     CALLING STANDARD PASCAL
     PARAMETERS(str BY REFERENCE STRING, return STRING);
END TEST_DLL
3) Create Procedure:
CREATE OR REPLACE
PROCEDURE TESTPRO AS
newStrIn varchar2(40) :='test';
newStrOut varchar2(256);
BEGIN
newStrOut := TEST.strNew(newStrIn);
DBMS_OUTPUT.PUT_LINE('newStrOut = ' || newStrOut );
DBMS_OUTPUT.PUT_LINE('newStrIn = ' || newStrIn );
END TESTPRO;
4) Run procedure the result following:
newStrOut = String is not null.(it correct)
newStrIn= 8!(it wrong, the newStrIn='String is not null' is correct))
I not found root cause why in pl/sql, I can't get the variable reference from dll c.
Please help me.
Quan.

Answer 1

For compatibility purposes you would probably be better using 10g development rather than 9i if you are going to use a 10g database. I'm not familiar with the latest versions in terms of Oracle Forms, cos I stopped developing in Forms back on version 8.
Essentially there are different components you can download and install.
Database - This sets up a database server and allows you to create databases to store your data in.
Client - This installs the necessary client software to allow you to connect to a database on a database server. It includes client software such as SQL*Plus and the drivers needed to make the connections.
Developer - This is a client side development environment for developing forms and reports. It requires the Client software in order to be able to connect to the database.
By the sounds of it you have downloaded and installed the last two, but without the first one you don't have a database to connect to.