— Function: gpgme_error_t gpgme_set_protocol (gpgme_ctx_t ctx, gpgme_protocol_t proto)

The function gpgme_set_protocol sets the protocol used within the context ctx to proto. All crypto operations will be performed by the crypto engine configured for that protocol. See Protocols and Engines.

Setting the protocol with gpgme_set_protocol does not check if the crypto engine for that protocol is available and installed correctly. See Engine Version Check.

The function returns the error code GPG_ERR_NO_ERROR if the protocol could be set successfully, and GPG_ERR_INV_VALUE if protocol is not a valid protocol.

— Function: gpgme_protocol_t gpgme_get_protocol (gpgme_ctx_t ctx)

The function gpgme_get_protocol retrieves the protocol currently use with the context ctx.