I am trying to create a proof of concept using sipa's secp256k1 library (

https://github.com/bitcoin/secp256k1) to find the public key of a given private key. However the code does not have much documentation so I am having trouble following it.

I believe the appropriate method to use is:

secp256k1_ecdsa_pubkey_create(unsigned char *pubkey, int *pubkeylen, const unsigned char *seckey, int compressed)

However I'm not sure exactly how it should be called. If anyone is familiar with using this, I would appreciate any direction.