database connection without using DSN

hi,
i am interacting with database, which is lying on server, through vc++ application.
at present i am using “SQLConnect()” to connect my application with oracle database in which one of the parameters is “Data Source Name(DSN)”.
is there any other way to connect it with oracle without using DSN or just using ip address and port number of the server or something like that??
in short i dont want to use DSN.
my application is already through so i cant go for the major changes inthat, so plzz suggest me some minor changes by which i can ommit the DSN stuff.
waiting for ur reply,
with best regards,
prakash..