How to find PBC pair?

Question

I am using PBC library for cryptographic operations writing in C++ and I am stack in finding how to put two element like

C = (g^r , H(X))

.

For pairing operation, for eg:

e(g^r , H(X))

can be used with element_pairing(pp, g^r, H(X))

But for normal two elements putting like this together C = (g^r , H(X)), what function can I use from PBC?