EVP_DigestSignInit.pod: Clarification in EVP_DigestSignFinal() parameter 'sig'
@@ -118,8 +118,9 @@ EVP_DigestSignUpdate() hashes I<cnt> bytes of data at I<d> into the
signature context I<ctx>. This function can be called several times on the
same I<ctx> to include additional data.
-EVP_DigestSignFinal() signs the data in I<ctx> and places the signature in I<sig>.
-If I<sig> is NULL then the maximum size of the output buffer is written to
+Unless I<sig> is NULL EVP_DigestSignFinal() signs the data in I<ctx>
+and places the signature in I<sig>.
+Otherwise the maximum necessary 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
