-using B<ctx>. The data to be signed is specified using the B<tbs> and
-B<tbslen> parameters. If B<sig> is B<NULL> then the maximum size of the output
-buffer is written to the B<siglen> parameter. If B<sig> is not B<NULL> then
-before the call the B<siglen> parameter should contain the length of the
-B<sig> buffer, if the call is successful the signature is written to
-B<sig> and the amount of data written to B<siglen>.
+using I<ctx>. The data to be signed is specified using the I<tbs> and
+I<tbslen> parameters. If I<sig> is NULL then the maximum size of the output
+buffer is written to the I<siglen> parameter. If I<sig> is not NULL then
+before the call the I<siglen> parameter should contain the length of the
+I<sig> buffer, if the call is successful the signature is written to
+I<sig> and the amount of data written to I<siglen>.