Add a directory containing certificate authority files to be used for performing verification.
void add_verify_path( const std::string & path, boost::system::error_code & ec);
This function is used to specify the name of a directory containing certification authority certificates. Each file in the directory must contain a single certificate. The files must be named using the subject name's hash and an extension of ".0".
The name of a directory containing the certificates.
Set to indicate what error occurred, if any.