cant connect c and mysql

[naveen chakravarthi]

Sir,
i have installed xampp which has inbuilt mysql in it..version is 5.1. mysql is working fine in open terminal , but when am trying to connect mysql server thru c program am getting an error message like 'cant connect to mysql server ,/var/lib/mysql/mysql.sock not present.'
in my.cnf file i have mentioned the path as /opt/lampp/var/mysql/mysql.sock. dunno why it is still trying to connect thru /var/lib/mysql/mysql.sock.
the c program is just a simple program which establishes a connection with the server and shows all the databases in it.
can you please help me out.