2 files changed, 11 insertions, 0 deletions
diff --git a/include/conts/conts.h b/include/conts/conts.h
index 7f30873..a49a00c 100644
--- a/include/conts/conts.h
+++ b/include/conts/conts.h
@@ -4,6 +4,16 @@
 #define CONTS_JOIN2(a, b) a##_##b
 #define CONTS_JOIN(a, b) CONTS_JOIN2(a, b)
 
+#if !defined(__has_attribute)
+#define __has_attribute(x) 0
+#endif
+
+#if __has_attribute(format)
+#define CONTS_FMT(func, x, y) __attribute__ ((format(func, x, y)))
+#else
+#define CONTS_FMT(func, x, y)
+#endif
+
 #define CONTAINER_OF(ptr, type, member) \
 	(type *)((char *)(ptr) - offsetof(type, member))
 
diff --git a/include/conts/sp.h b/include/conts/sp.h
index 73fcdda..2f88293 100644
--- a/include/conts/sp.h
+++ b/include/conts/sp.h
@@ -201,6 +201,7 @@ static inline int SP(append_vfmt)(struct SP_STRUCT *s, const char *fmt, va_list
 	return 0;
 }
 
+CONTS_FMT(__printf__, 2, 3)
 static inline int SP(append_fmt)(struct SP_STRUCT *s, const char *fmt, ...)
 {
 	int r = 0;