[master] 85eeae6 Make the (v)bprintf() macros also check for negative return values.

[Poul-Henning Kamp]

commit 85eeae6b98f7a87000d5e85beb4f6d4bd55d6168
Author: Poul-Henning Kamp <phk at FreeBSD.org>
Date:   Thu Sep 14 16:22:35 2017 +0000

    Make the (v)bprintf() macros also check for negative return values.

diff --git a/include/vdef.h b/include/vdef.h
index af51c47..b7fee8b 100644
--- a/include/vdef.h
+++ b/include/vdef.h
@@ -38,15 +38,17 @@
 /* Safe printf into a fixed-size buffer */
 #define bprintf(buf, fmt, ...)						\
 	do {								\
-		assert(snprintf(buf, sizeof buf, fmt, __VA_ARGS__)	\
-		    < sizeof buf);					\
+		int ibprintf;						\
+		ibprintf = snprintf(buf, sizeof buf, fmt, __VA_ARGS__);	\
+		assert(ibprintf >= 0 && ibprintf < sizeof buf);		\
 	} while (0)
 
 /* Safe printf into a fixed-size buffer */
 #define vbprintf(buf, fmt, ap)						\
 	do {								\
-		assert(vsnprintf(buf, sizeof buf, fmt, ap)		\
-		    < sizeof buf);					\
+		int ivbprintf;						\
+		ivbprintf = vsnprintf(buf, sizeof buf, fmt, ap);	\
+		assert(ivbprintf >= 0 && ivbprintf < sizeof buf);	\
 	} while (0)
 
 /* Close and discard filedescriptor */