[Interest] Oracle client does not read tnsnames.ora

[Mathias Waack]

Hello,

I have to fix a bug in an older application which connects to an oracle 
DB. I was able to compile and start the app with Qt 5.6, but the connect 
to Oracle fails  with ORA-12545. That is a bit surprising, because tools 
like sqlplus run on the same machine in the same environment. strace 
shows, that the app  does not read the tnsnames.ora file:

strace -f 
../build-suptool.linux-Desktop_Qt_5_6_2_GCC_64bit2-Debug/suptoolserver 
-c server/maw_server.cfg  2>&1 |grep "\.ora"
lstat("/usr/lib/oracle/12.2/client64/env.ora", 0x7ffd48cd0a60) = -1 
ENOENT (No such file or directory)
open("/usr/lib/oracle/12.2/client64/env.ora", O_RDONLY) = -1 ENOENT (No 
such file or directory)
access("/usr/lib/oracle/12.2/client64/network/admin/sqlnet.ora", F_OK) = 0
open("/usr/lib/oracle/12.2/client64/network/admin/sqlnet.ora", O_RDONLY) = 4
access("/home/mwaack/.sqlnet.ora", F_OK) = -1 ENOENT (No such file or 
directory)
access("/usr/lib/oracle/12.2/client64/network/admin/sqlnet.ora", F_OK) = 0
open("/usr/lib/oracle/12.2/client64/network/admin/sqlnet.ora", O_RDONLY) = 7
access("/etc/intchg.ora", F_OK)         = -1 ENOENT (No such file or 
directory)
access("/usr/lib/oracle/12.2/client64/network/admin/intchg.ora", F_OK) = 
-1 ENOENT (No such file or directory)
access("/etc/tnsnav.ora", F_OK)         = -1 ENOENT (No such file or 
directory)
access("/usr/lib/oracle/12.2/client64/network/admin/tnsnav.ora", F_OK) = 
-1 ENOENT (No such file or directory)

The connect to the database is straight forward:

   oradb = QSqlDatabase::addDatabase("QOCI","oradb");
   if (!oradb.isValid()) throw ServerError("cannot load oracle database");
   settings.beginGroup("db");
   oradb.setDatabaseName(settings.value("name").toString());
   oradb.setUserName(settings.value("user").toString());
   oradb.setPassword(settings.value("pass").toString());
   Q_ASSERT(oradb.hostName().isEmpty());
   bool ok = oradb.open();

The last call to oradb.open() fails.

ORACLE_HOME is set correctly (obviously the oracle libs are able to find 
the sqlnet.ora), I've also tried setting/unsetting TNS_ADMIN, without 
any result. I am using the instant client for oracle.

So I am fairly sure this is not a Qt problem, but I hope to find someone 
using Oracle from Qt who have a clue whats going on here.

Mathias