+@node Signature Notation Data
+@subsubsection Signature Notation Data
+@cindex notation data
+@cindex signature notation data
+@cindex policy URL
+
+Using the following functions, you can attach arbitrary notation data
+to a signature. This information is then available to the user when
+the signature is verified.
+
+@deftypefun void gpgme_sig_notation_clear (@w{gpgme_ctx_t @var{ctx}})
+The function @code{gpgme_sig_notation_clear} removes the notation data
+from the context @var{ctx}. Subsequent signing operations from this
+context will not include any notation data.
+
+Every context starts with an empty notation data list.
+@end deftypefun
+
+@deftypefun gpgme_error_t gpgme_sig_notation_add (@w{gpgme_ctx_t @var{ctx}}, @w{const char *@var{name}}, @w{const char *@var{value}}, @w{gpgme_sig_notation_flags_t @var{flags}})
+The function @code{gpgme_sig_notation_add} adds the notation data with
+the name @var{name} and the value @var{value} to the context
+@var{ctx}.
+
+Subsequent signing operations will include this notation data, as well
+as any other notation data that was added since the creation of the
+context or the last @code{gpgme_sig_notation_clear} operation.
+
+The arguments @var{name} and @var{value} must be @code{NUL}-terminated
+strings in human-readable form. The flag
+@code{GPGME_SIG_NOTATION_HUMAN_READABLE} is implied
+(non-human-readable notation data is currently not supported). The
+strings must be in UTF-8 encoding.
+
+If @var{name} is @code{NULL}, then @var{value} should be a policy URL.
+
+The function @code{gpgme_sig_notation_add} returns the error code
+@code{GPG_ERR_NO_ERROR} if the notation data could be added
+successfully, @code{GPG_ERR_INV_VALUE} if @var{ctx} is not a valid
+pointer, or if @var{name}, @var{value} and @var{flags} are an invalid
+combination. The function also passes through any errors that are
+reported by the crypto engine support routines.
+@end deftypefun
+
+@deftypefun gpgme_sig_notation_t gpgme_sig_notation_get (@w{const gpgme_ctx_t @var{ctx}})
+The function @code{gpgme_sig_notation_get} returns the linked list of
+notation data structures that are contained in the context @var{ctx}.
+
+If @var{ctx} is not a valid pointer, or there is no notation data
+added for this context, @code{NULL} is returned.
+@end deftypefun
+
+