However, this is not where the value for the Oracle Home is stored for an Oracle 10g installation. The ORACLE_HOME key in 10g is at:
HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\KEY_<install name>\ORACLE_HOME
e.g.:
HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\KEY_OraClient10g_home1\ORACLE_HOME
Thus, when you execute the 4D for OCI command "OCIGetTnsnamesPath" you do not get the correct location of the Oracle Home with Oracle 10g.
As a workaround you can modify the Windows Registry so that the command still works.
WARNING: Do not proceed if you are not comfortable with modifying the Windows Registry.
It is recommended that you make a backup of the Registry before proceeding, or at least export the Oracle Registry keys.
To make the modifications:
1. Open the Microsoft Registry editor
2. Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE
3. If the String Value for ORACLE_HOME does not exist, create it
4. Modify the String Value "ORACLE_HOME" to point to the same location as:
HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\KEY_<install name>\ORACLE_HOME
5. Quit the Microsoft Registry editor
Now the 4D for OCI command OCIGetTnsnamesPath should return the correct Oracle Home for your Oracle installation.