doc: BN_free() is NULL-safe

document that parameter to BN_free can be NULL

backport from master

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4439)

diff --git a/doc/crypto/BN_new.pod b/doc/crypto/BN_new.pod
index ab7a105e3ad7e9f19b3ab386c9f3888dff17b93c..413a1ea842a97b855d218aa2570b5bf0bb0224c7 100644 (file)
--- a/doc/crypto/BN_new.pod
+++ b/doc/crypto/BN_new.pod
@@ -30,6 +30,7 @@ to the value 0.
 BN_free() frees the components of the B<BIGNUM>, and if it was created
 by BN_new(), also the structure itself. BN_clear_free() additionally
 overwrites the data before the memory is returned to the system.
+If B<a> is NULL, nothing is done.
 
 =head1 RETURN VALUES