bio: note that BIO_sprintf null terminates on insufficient space.

Fixes: #14772
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14829)

diff --git a/doc/man3/BIO_printf.pod b/doc/man3/BIO_printf.pod
index 2d7c230308c7d16c6090a537d0a13c7b3d66666c..ce3e6b31ad6950f9672ffb9eb52d6687bdb7f7f5 100644 (file)
--- a/doc/man3/BIO_printf.pod
+++ b/doc/man3/BIO_printf.pod
@@ -18,16 +18,16 @@ BIO_printf, BIO_vprintf, BIO_snprintf, BIO_vsnprintf
 =head1 DESCRIPTION
 
 BIO_printf() is similar to the standard C printf() function, except that
-the output is sent to the specified BIO, B<bio>, rather than standard
+the output is sent to the specified BIO, I<bio>, rather than standard
 output.  All common format specifiers are supported.
 
 BIO_vprintf() is similar to the vprintf() function found on many platforms,
-the output is sent to the specified BIO, B<bio>, rather than standard
+the output is sent to the specified BIO, I<bio>, rather than standard
 output.  All common format specifiers are supported. The argument
-list B<args> is a stdarg argument list.
+list I<args> is a stdarg argument list.
 
 BIO_snprintf() is for platforms that do not have the common snprintf()
-function. It is like sprintf() except that the size parameter, B<n>,
+function. It is like sprintf() except that the size parameter, I<n>,
 specifies the size of the output buffer.
 
 BIO_vsnprintf() is to BIO_snprintf() as BIO_vprintf() is to BIO_printf().
@@ -38,6 +38,12 @@ All functions return the number of bytes written, or -1 on error.
 For BIO_snprintf() and BIO_vsnprintf() this includes when the output
 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.
+
 =head1 COPYRIGHT
 
 Copyright 2017-2020 The OpenSSL Project Authors. All Rights Reserved.