How To Retrieving a List of All ODBC Data Sources

   #include <afxcoll.h>    //Needed for CStringList MFC class.
   #include "odbcinst.h"
   #include "sql.h"
   #include "sqlext.h"

   // NOTE: in 16-bit Visual C++ link with odbcinst.lib
   //       in 32-bit Visual C++ 2.x link with odbccp32.lib
   //       in 32-bit Visual C++ 4.x no need to change link options

   #define MAX_DSN_LENGTH 30
   #define MAX_DSN_DESC_LENGTH 300

   BOOL GetODBCDataSourceNames(CStringList * pList)
   {
       HENV hEnv;
       char szDSN[MAX_DSN_LENGTH];
       SWORD cbDSN;
       UCHAR szDescription[MAX_DSN_DESC_LENGTH];
       SWORD cbDescription;
       RETCODE retcode;

       ASSERT(pList->IsEmpty());
       if (SQLAllocEnv(&hEnv)!=SQL_SUCCESS)
           return FALSE;

       while (retcode=SQLDataSources(hEnv, SQL_FETCH_NEXT,
                    (UCHAR FAR *) &szDSN, MAX_DSN_LENGTH, &cbDSN,
                    (UCHAR FAR *) &szDescription,MAX_DSN_DESC_LENGTH,
                     &cbDescription) != SQL_NO_DATA_FOUND
                    &&retcode!=SQL_ERROR)

          {
               pList->AddTail(szDSN);
          }

       SQLFreeEnv(hEnv);
       if (retcode==SQL_ERROR)
         return FALSE;

       return TRUE;
   }