1 files changed, 2 insertions, 0 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 61574b5ee..b9852345f 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -1079,9 +1079,11 @@ uint16_t xatou16(const char *numstr) FAST_FUNC;
 #if ENABLE_FLOAT_DURATION
 typedef double duration_t;
 void sleep_for_duration(duration_t duration) FAST_FUNC;
+#define DURATION_FMT "f"
 #else
 typedef unsigned duration_t;
 #define sleep_for_duration(duration) sleep(duration)
+#define DURATION_FMT "u"
 #endif
 duration_t parse_duration_str(char *str) FAST_FUNC;