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.
gpgme_sig_notation_clearremoves the notation data from the context ctx. Subsequent signing operations from this context will not include any notation data.
Every context starts with an empty notation data list.
gpgme_sig_notation_addadds the notation data with the name name and the value value to the context 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
The arguments name and value must be
NUL-terminated strings in human-readable form. The flag
GPGME_SIG_NOTATION_HUMAN_READABLEis implied (non-human-readable notation data is currently not supported). The strings must be in UTF-8 encoding.
If name is
NULL, then value should be a policy URL.
gpgme_sig_notation_addreturns the error code
GPG_ERR_NO_ERRORif the notation data could be added successfully,
GPG_ERR_INV_VALUEif ctx is not a valid pointer, or if name, value and flags are an invalid combination. The function also passes through any errors that are reported by the crypto engine support routines.
gpgme_sig_notation_getreturns the linked list of notation data structures that are contained in the context ctx.
If ctx is not a valid pointer, or there is no notation data added for this context,