You can change the configuration of a backend engine, and thus change the executable program and configuration directory to be used. You can make these changes the default or set them for some contexts individually.
gpgme_set_engine_infochanges the default configuration of the crypto engine implementing the protocol proto.
file_name is the file name of the executable program implementing this protocol, and home_dir is the directory name of the configuration directory for this crypto engine. If home_dir is
NULL, the engine's default will be used.
The new defaults are not applied to already created GPGME contexts.
This function returns the error code
GPG_ERR_NO_ERRORif successful, or an eror code on failure.
gpgme_ctx_set_engine_info can be used to change the engine
configuration per context. See Crypto Engine.