n : <span><a href="../Types/PkSigning/index.html#type-t">Types.PkSigning.t</a> Ctypes_static.ptr</span> <span>&#45;&gt;</span> <span>unit Ctypes_static.ptr</span> <span>&#45;&gt;</span> Unsigned.size_t <span>&#45;&gt;</span> <span>unit Ctypes_static.ptr</span> <span>&#45;&gt;</span> Unsigned.size_t <span>&#45;&gt;</span> Unsigned.size_t</code></dt><dd><p><code>pk_sign sign msg msg_len signature signature_len</code></p><p>Sign a message. The signature will be written to the signature buffer. Returns olm_erro