Document the output of timespec_str() better

It can be as short as 12 chars: "-0.123456789"
Or as long as 21 chars: "-2147483647.123456789"

1 files changed, 12 insertions, 0 deletions

diff --git a/gpsutils.c b/gpsutils.c
index 8c9525ff..7184566a 100644
--- a/gpsutils.c
+++ b/gpsutils.c
@@ -489,6 +489,18 @@ double earth_distance(double lat1, double lon1, double lat2, double lon2)
  * put in it *buf, buf should be at least 22 bytes
  * return negative for error
  * otherwise the number of chars in buf, excluding trailing \0
+ *
+ * the returned buffer will look like, shortest case:
+ *    sign character ' ' or '-'
+ *    one digit of seconds
+ *    decmal point '.'
+ *    9 digits of nanoSec
+ *
+ * So 12 chars, like this: "-0.123456789"
+ *
+ * Absolute worst case is 10 digits of seconds.  
+ * So 21 digits like this: "-2147483647.123456789"
+ *
 */
 int timespec_str(struct timespec *ts, /*@out@*/char *buf, int buf_size)
 {