Re: mktime() hangs for dates before 1970

[Paul Eggert]

On 01/30/2011 01:17 AM, Ralf Wildenhues wrote:
> just to avoid surprises on new
> systems, why not use this:
> 
>   #elif defined(LLONG_MAX) && INT_MAX <= LLONG_MAX / 2
>   typedef long long int long_int;
>   #else
>   # error "need a type that is wider than int"
>   #endif

Thanks for mentioning this.
Although long_int width is already checked elsewhere,
the code can be reorganized to make the check clearer.
I pushed this:

---
 ChangeLog    |    8 ++++++++
 lib/mktime.c |   11 +++++------
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index c05c36f..2d57a0a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2011-01-30  Paul Eggert  <address@hidden>
+
+       mktime: clarify long_int width checking
+       * lib/mktime.c (long_int_is_wide_enough): Move this assertion to
+       the top level, to make it clearer that the assumption about
+       long_int width is being checked.  See
+       <http://lists.gnu.org/archive/html/bug-gnulib/2011-01/msg00554.html>.
+
 2011-01-30  Simon Josefsson  <address@hidden>
 
        ignore-value: Fix self-test.
diff --git a/lib/mktime.c b/lib/mktime.c
index 2486514..cba2b8b 100644
--- a/lib/mktime.c
+++ b/lib/mktime.c
@@ -64,12 +64,16 @@
 # define mktime my_mktime
 #endif /* DEBUG */
 
+/* Verify a requirement at compile-time (unlike assert, which is runtime).  */
+#define verify(name, assertion) struct name { char a[(assertion) ? 1 : -1]; }
+
 /* A signed type that is at least one bit wider than int.  */
 #if INT_MAX <= LONG_MAX / 2
 typedef long int long_int;
 #else
 typedef long long int long_int;
 #endif
+verify (long_int_is_wide_enough, INT_MAX == INT_MAX * (long_int) 2 / 2);
 
 /* Shift A right by B bits portably, by dividing A by 2**B and
    truncating towards minus infinity.  A and B should be free of side
@@ -123,9 +127,6 @@ typedef long long int long_int;
 #endif
 #define TIME_T_MIDPOINT (SHR (TIME_T_MIN + TIME_T_MAX, 1) + 1)
 
-/* Verify a requirement at compile-time (unlike assert, which is runtime).  */
-#define verify(name, assertion) struct name { char a[(assertion) ? 1 : -1]; }
-
 verify (time_t_is_integer, TYPE_IS_INTEGER (time_t));
 verify (twos_complement_arithmetic,
         (TYPE_TWOS_COMPLEMENT (int)
@@ -196,8 +197,6 @@ ydhms_diff (long_int year1, long_int yday1, int hour1, int 
min1, int sec1,
             int year0, int yday0, int hour0, int min0, int sec0)
 {
   verify (C99_integer_division, -1 / 2 == 0);
-  verify (long_int_year_and_yday_are_wide_enough,
-          INT_MAX == INT_MAX * (long_int) 2 / 2);
 
   /* Compute intervening leap days correctly even if year is negative.
      Take care to avoid integer overflow here.  */
@@ -733,6 +732,6 @@ main (int argc, char **argv)
 
 /*
 Local Variables:
-compile-command: "gcc -DDEBUG -Wall -W -O2 -g mktime.c -o mktime"
+compile-command: "gcc -DDEBUG -I. -Wall -W -O2 -g mktime.c -o mktime"
 End:
 */
-- 
1.7.3