VC++ 2008 Express Edition, OCCI oraocci10d.dll 10.2.0.1, DB Oracle 10g

Question

I am not able to run some basic code using OCCI. I am able to successfully compile and link the code.
using namespace oracle::occi;
class occidml
private:
     Environment *env;
     Connection *conn;
     Statement *stmt;
public:
     occidml(string user, string passwd,string db)
          //env = Environment::createEnvironment(Environment::DEFAULT);
          env = Environment::createEnvironment();
          conn = env->createConnection(user, passwd,db);
Every time the constructor is called, it successfully creates the environment it appears, I have a watch on the env pointer and it has some address. But the createConnection fails so I catch the exception and try to getMessage, but that fails with
"Unhandled exception at 0x005b8dcb in Oracle_Proj.exe: 0xC0000005: Access violation reading location 0xcccccccc."
I am using the occi sample code and havent changed much. please help me. I have a long way to go to make the app work. I can provide you with any additional information required.
Chad

Answer 1

My suspicion is that you are using mismatched versions between OCCI/Oracle Client and the Microsoft runtime libraries. That's why I've asked about the versions. I don't know what version of OCCI/Oracle Client you are using, but if it is the version that ships with Oracle Database Expression Edition, that will be incorrect since that version is for VS2003/VC7.1. One potential issue when using mismatched versions is that the memory allocators/deallocators used to build OCCI may be different from the runtime versions, for example.
EDIT1: Also, if using the debug build, you'll need to make sure that the oraocciXXd.dll is in the path. If it's not you should get an "application unable to start" type of message though. I don't have an Oracle Database Express Edition install handy at the moment, so I'm going somewhat from memory.
Thanks,
Mark
Edited by: Mark Williams on Sep 1, 2010 1:42 PM