RT3462: Document actions when data==NULL
If data is NULL, return the size needed to hold the
derived key. No other API to do this, so document
the behavior.
Reviewed-by: Richard Levitte <levitte@openssl.org>
diff --git a/doc/crypto/EVP_BytesToKey.pod b/doc/crypto/EVP_BytesToKey.pod
index d07ae6c..cd3aa02 100644
--- a/doc/crypto/EVP_BytesToKey.pod
+++ b/doc/crypto/EVP_BytesToKey.pod
@@ -55,7 +55,10 @@
=head1 RETURN VALUES
-EVP_BytesToKey() returns the size of the derived key in bytes, or 0 on error.
+If B<data> is NULL, then EVP_BytesToKey() returns the number of bytes
+needed to store the derived key.
+Otherwise, EVP_BytesToKey() returns the size of the derived key in bytes,
+or 0 on error.
=head1 SEE ALSO
