parse-duration: various small improvements.

1 files changed, 9 insertions, 3 deletions

diff --git a/lib/parse-duration.h b/lib/parse-duration.h
index 7ecc7dbe0b..fbc732ff39 100644
--- a/lib/parse-duration.h
+++ b/lib/parse-duration.h
@@ -47,9 +47,11 @@
     yy Y mm M ww W dd D
 
   or it may be empty and followed by a 'T'.  The "yyyymmdd" must be eight
-  digits long.  Note:  months are always 30 days and years are always 365
-  days long.  5 years is always 1825, not 1826 or 1827 depending on leap
-  year considerations.  3 months is always 90 days.  There is no consideration
+  digits long.
+
+  NOTE!  Months are always 30 days and years are always 365 days long.
+  5 years is always 1825 days, not 1826 or 1827 depending on leap year
+  considerations.  3 months is always 90 days.  There is no consideration
   for how many days are in the current, next or previous months.
 
   For the final format:
@@ -75,8 +77,12 @@
 
 #include <time.h>
 
+/* Return value when a valid duration cannot be parsed.  */
 #define BAD_TIME        ((time_t)~0)
 
+/* Parses the given string.  If it has the syntax of a valid duration,
+   this duration is returned.  Otherwise, the return value is BAD_TIME,
+   and errno is set to either EINVAL (bad syntax) or ERANGE (out of range).  */
 extern time_t parse_duration(char const * in_pz);
 
 #endif /* GNULIB_PARSE_DURATION_H */