BIO_printf.pod: Clarify that output is always null terminated.

The original text was ambiguous about termination for errors other
than insufficient space.  See issue #14772.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15000)

diff --git a/doc/man3/BIO_printf.pod b/doc/man3/BIO_printf.pod
index d7a59a36fd2208941738be8f97e03343ed509c64..221881d123cabb31801ac25ff15dc5b9d320631b 100644 (file)
--- a/doc/man3/BIO_printf.pod
+++ b/doc/man3/BIO_printf.pod
@@ -40,9 +40,10 @@ buffer is too small.
 
 =head1 NOTES
 
-Except when I<n> is 0, both BIO_snprintf() and BIO_vsnprintf() terminate
-their output with C<'\0'> even when there is insufficient space to output
-the whole string.
+Except when I<n> is 0, both BIO_snprintf() and BIO_vsnprintf() always
+terminate their output with C<'\0'>.  This includes cases where -1 is
+returned, such as when there is insufficient space to output the whole
+string.
 
 =head1 COPYRIGHT