1 files changed, 38 insertions, 0 deletions
diff --git a/libntp/msyslog.c b/libntp/msyslog.c
index 9682d3002119..9a18c4d0d7b0 100644
--- a/libntp/msyslog.c
+++ b/libntp/msyslog.c
@@ -582,3 +582,41 @@ setup_logfile(
 		msyslog(LOG_ERR, "Cannot reopen log file %s, %m",
 			syslog_fname);
 }
+
+/* Helper for unit tests, where stdout + stderr are piped to the same
+ * stream.  This works moderately reliable only if both streams are
+ * unbuffered or line buffered.  Unfortunately stdout can be fully
+ * buffered on pipes or files...
+ */
+int
+change_iobufs(
+	int how
+	)
+{
+	int	retv = 0;
+	
+#   ifdef HAVE_SETVBUF
+
+	int mode;
+
+	switch (how) {
+	case 0 : mode = _IONBF; break; /* no buffering   */
+	case 1 : mode = _IOLBF; break; /* line buffering */
+	case 2 : mode = _IOFBF; break; /* full buffering */
+	default: mode = _IOLBF; break; /* line buffering */
+	}
+	
+	retv = 1;
+	if (setvbuf(stdout, NULL, mode, BUFSIZ) != 0)
+		retv = -1;
+	if (setvbuf(stderr, NULL, mode, BUFSIZ) != 0)
+		retv = -1;
+
+#   else
+	
+	UNUSED_ARG(how);
+	
+#   endif
+	
+	return retv;
+}