2 files changed, 6 insertions, 4 deletions

diff --git a/src/lib/libcrypto/bio/b_print.c b/src/lib/libcrypto/bio/b_print.c
index fbff331796..880dc69303 100644
--- a/src/lib/libcrypto/bio/b_print.c
+++ b/src/lib/libcrypto/bio/b_print.c
@@ -806,6 +806,7 @@ int BIO_vprintf (BIO *bio, const char *format, va_list args)
         }
 
 /* As snprintf is not available everywhere, we provide our own implementation.
+ * In case of overflow or error, this returns -1.
  * This function has nothing to do with BIOs, but it's closely related
  * to BIO_printf, and we need *some* name prefix ...
  * (XXX  the function should be renamed, but to what?) */
@@ -830,10 +831,10 @@ int BIO_vsnprintf(char *buf, size_t n, const char *format, va_list args)
         _dopr(&buf, NULL, &n, &retlen, &truncated, format, args);
 
         if (truncated)
-                /* In case of truncation, return -1 like traditional snprintf.
+                /* In case of truncation, return -1 unlike traditional snprintf.
                  * (Current drafts for ISO/IEC 9899 say snprintf should return
                  * the number of characters that would have been written,
-                 * had the buffer been large enough.) */
+                 * had the buffer been large enough, as it did historically.) */
                 return -1;
         else
                 return (retlen <= INT_MAX) ? (int)retlen : -1;
diff --git a/src/lib/libssl/src/crypto/bio/b_print.c b/src/lib/libssl/src/crypto/bio/b_print.c
index fbff331796..880dc69303 100644
--- a/src/lib/libssl/src/crypto/bio/b_print.c
+++ b/src/lib/libssl/src/crypto/bio/b_print.c
@@ -806,6 +806,7 @@ int BIO_vprintf (BIO *bio, const char *format, va_list args)
         }
 
 /* As snprintf is not available everywhere, we provide our own implementation.
+ * In case of overflow or error, this returns -1.
  * This function has nothing to do with BIOs, but it's closely related
  * to BIO_printf, and we need *some* name prefix ...
  * (XXX  the function should be renamed, but to what?) */
@@ -830,10 +831,10 @@ int BIO_vsnprintf(char *buf, size_t n, const char *format, va_list args)
         _dopr(&buf, NULL, &n, &retlen, &truncated, format, args);
 
         if (truncated)
-                /* In case of truncation, return -1 like traditional snprintf.
+                /* In case of truncation, return -1 unlike traditional snprintf.
                  * (Current drafts for ISO/IEC 9899 say snprintf should return
                  * the number of characters that would have been written,
-                 * had the buffer been large enough.) */
+                 * had the buffer been large enough, as it did historically.) */
                 return -1;
         else
                 return (retlen <= INT_MAX) ? (int)retlen : -1;