diff --git a/libowlps/libowlps.c b/libowlps/libowlps.c
index b859ecb..2886fc5 100644
--- a/libowlps/libowlps.c
+++ b/libowlps/libowlps.c
@@ -95,7 +95,7 @@ uint_fast8_t frequency_to_channel(uint_fast16_t channel)
  */
 void timestamp_now(TIMESTAMP *now)
 {
-  if (timestamp_now_ns(now))
+  if (! timestamp_now_ns(now))
     timestamp_round_to_ms(now) ;
 }
 
@@ -104,14 +104,15 @@ void timestamp_now(TIMESTAMP *now)
 /*
  * Set the TIMESTAMP 'now' at the current time (nanosecond-precision).
  */
-BOOL timestamp_now_ns(TIMESTAMP *now)
+int timestamp_now_ns(TIMESTAMP *now)
 {
-  if (clock_gettime(CLOCK_REALTIME, now))
+  int ret ;
+  if ((ret = clock_gettime(CLOCK_REALTIME, now)))
     {
       perror("Cannot get the current time") ;
-      return FALSE ;
+      return ret ;
     }
-  return TRUE ;
+  return 0 ;
 }
 
 
diff --git a/libowlps/owlps.h b/libowlps/owlps.h
index e1cc831..85c6d18 100644
--- a/libowlps/owlps.h
+++ b/libowlps/owlps.h
@@ -224,7 +224,7 @@ uint_fast8_t frequency_to_channel(uint_fast16_t channel) ;
 
 // Time
 void timestamp_now(TIMESTAMP *now) ;
-BOOL timestamp_now_ns(TIMESTAMP *now) ;
+int timestamp_now_ns(TIMESTAMP *now) ;
 void timestamp_round_to_ms(TIMESTAMP *now) ;
 TIMESTAMP timeval_to_timestamp(const struct timeval d) ;
 uint64_t timestamp_to_ms(TIMESTAMP date) ;