Y2038: add function __difftime64
Commit Message
* __difftime: provide a 64-bit-time version (but do not assume
__time64_t is a signed int so that Gnulib can reuse the code)
and make the 32-bit version a wrapper of it.
---
This patch is part of the Y2038 patch series, which is available at
<https://sourceware.org/git/?p=glibc.git;a=shortlog;h=refs/heads/aaribaud/y2038>.
Warning: this branch may be rebased on current master and/or updated based on
feedback from the list at any time.
include/time.h | 6 ++++++
time/difftime.c | 31 ++++++++++++++++++++++---------
2 files changed, 28 insertions(+), 9 deletions(-)
@@ -125,6 +125,12 @@ extern char * __strptime_internal (const char *rp, const char *fmt,
struct tm *tm, void *statep,
locale_t locparam) attribute_hidden;
+#if __TIMESIZE == 64
+# define __difftime64 __difftime
+#else
+extern double __difftime64 (__time64_t time1, __time64_t time0);
+#endif
+
extern double __difftime (time_t time1, time_t time0);
/* Use in the clock_* functions. Size of the field representing the
@@ -31,9 +31,9 @@
time_t is known to be an integer type. */
static double
-subtract (time_t time1, time_t time0)
+subtract (__time64_t time1, __time64_t time0)
{
- if (! TYPE_SIGNED (time_t))
+ if (! TYPE_SIGNED (__time64_t))
return time1 - time0;
else
{
@@ -76,9 +76,9 @@ subtract (time_t time1, time_t time0)
1 is unsigned in C, so it need not be compared to zero. */
uintmax_t hdt = dt / 2;
- time_t ht1 = time1 / 2;
- time_t ht0 = time0 / 2;
- time_t dht = ht1 - ht0;
+ __time64_t ht1 = time1 / 2;
+ __time64_t ht0 = time0 / 2;
+ __time64_t dht = ht1 - ht0;
if (2 < dht - hdt + 1)
{
@@ -99,18 +99,18 @@ subtract (time_t time1, time_t time0)
/* Return the difference between TIME1 and TIME0. */
double
-__difftime (time_t time1, time_t time0)
+__difftime64 (__time64_t time1, __time64_t time0)
{
/* Convert to double and then subtract if no double-rounding error could
result. */
- if (TYPE_BITS (time_t) <= DBL_MANT_DIG
- || (TYPE_FLOATING (time_t) && sizeof (time_t) < sizeof (long double)))
+ if (TYPE_BITS (__time64_t) <= DBL_MANT_DIG
+ || (TYPE_FLOATING (__time64_t) && sizeof (__time64_t) < sizeof (long double)))
return (double) time1 - (double) time0;
/* Likewise for long double. */
- if (TYPE_BITS (time_t) <= LDBL_MANT_DIG || TYPE_FLOATING (time_t))
+ if (TYPE_BITS (__time64_t) <= LDBL_MANT_DIG || TYPE_FLOATING (__time64_t))
return (long double) time1 - (long double) time0;
/* Subtract the smaller integer from the larger, convert the difference to
@@ -118,4 +118,17 @@ __difftime (time_t time1, time_t time0)
return time1 < time0 ? - subtract (time0, time1) : subtract (time1, time0);
}
+
+/* Provide a 32-bit wrapper if needed */
+
+#if __TIMESIZE != 64
+
+double
+__difftime (time_t time1, time_t time0)
+{
+ return __difftime64 (time1, time0);
+}
+
+#endif
+
strong_alias (__difftime, difftime)