1 files changed, 13 insertions, 0 deletions
diff --git a/lib/libssl/src/doc/ssl/d2i_SSL_SESSION.pod b/lib/libssl/src/doc/ssl/d2i_SSL_SESSION.pod
index 4a6fb128214..d817f72b545 100644
--- a/lib/libssl/src/doc/ssl/d2i_SSL_SESSION.pod
+++ b/lib/libssl/src/doc/ssl/d2i_SSL_SESSION.pod
@@ -49,6 +49,19 @@ known limit on the size of the created ASN1 representation, so the necessary
 amount of space should be obtained by first calling i2d_SSL_SESSION() with
 B<pp=NULL>, and obtain the size needed, then allocate the memory and
 call i2d_SSL_SESSION() again.
+Note that this will advance the value contained in B<*pp> so it is necessary
+to save a copy of the original allocation.
+For example:
+ int i, j;
+ char *p, *temp;
+
+ i = i2d_SSL_SESSION(sess, NULL);
+ p = temp = malloc(i);
+ if (temp != NULL) {
+	j = i2d_SSL_SESSION(sess, &temp);
+	assert(i == j);
+	assert(p + i == temp);
+ }
 
 =head1 RETURN VALUES