isdigit() needs an unsigned char argument.

Per the C standard, the routine should be passed an int, with a value that's
representable as an unsigned char or EOF. Passing a signed char is wrong,
because a negative value is not representable as an unsigned char.
Unfortunately no compiler warns about that.

diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index 8ba3209fda5491629f35ebb14deb80e3e9f1cbca..ce30bb6e9fa65e503beeea7ccd9cf82bf050bd09 100644 (file)
--- a/src/backend/utils/adt/timestamp.c
+++ b/src/backend/utils/adt/timestamp.c
@@ -511,7 +511,7 @@ parse_sane_timezone(struct pg_tm *tm, text *zone)
         * as invalid, it's enough to disallow having a digit in the first
         * position of our input string.
         */
-       if (isdigit(*tzname))
+       if (isdigit((unsigned char) *tzname))
                ereport(ERROR,
                                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                                 errmsg("invalid input syntax for numeric time zone: \"%s\"",