cpp: Add convenience API to obtain remarks

* lang/cpp/src/key.h, lang/cpp/src/key.cpp (UserID::remark): New.

--
A remark made by one key on another is a signature notation on
a user id certification signature with the name "[email protected]".

This helps with:
GnuPG-Bug-Id: T4734

1 files changed, 17 insertions, 0 deletions

diff --git a/lang/cpp/src/key.h b/lang/cpp/src/key.h
index dd855aec..cca3c7a6 100644
--- a/lang/cpp/src/key.h
+++ b/lang/cpp/src/key.h
@@ -413,6 +413,23 @@ public:
      *
      * @returns the last update time. */
     time_t lastUpdate() const;
+
+    /*! Get a remark made by the key provided.
+     * A remark is a signature notation on
+     * this user id made by the key with the
+     * name "[email protected]". Returns an error if the
+     * parent key of this user id was not listed with the
+     * keylist mode flags for signatures and signature notations.
+     *
+     * @param key The key for which comments should be searched.
+     * @param error Set to GPG_ERR_NO_DATA if the keylist did
+     *              not include signature notations.
+     *
+     * @returns The value of the comment or NULL if none exists.
+     **/
+    const char *remark(const Key &key,
+                       Error &error) const;
+
 private:
     shared_gpgme_key_t key;
     gpgme_user_id_t uid;