difftime can throw exceptions

difftime can signal an inexact conversion when converting to double,
so it should not be marked as pure or nothrow (BZ 31808).

Although we could do something more complicated, in which difftime is
plain on modern platforms but const and nothrow on obsolescent
platforms with 32-bit time_t, it hardly seems worth the trouble.
difftime is used so rarely that it's not worth taking pains to
optimize calls to it on obsolescent platforms.

Reviewed-by: DJ Delorie <dj@redhat.com>

diff --git a/time/time.h b/time/time.h
index 486367f7dd7da5cb9e75740bf9413ac5a4002021..b6b439a45273ff4440372a42cde8cb7b4c87b194 100644 (file)
--- a/time/time.h
+++ b/time/time.h
@@ -76,8 +76,7 @@ extern clock_t clock (void) __THROW;
 extern time_t time (time_t *__timer) __THROW;
 
 /* Return the difference between TIME1 and TIME0.  */
-extern double difftime (time_t __time1, time_t __time0)
-     __THROW __attribute_pure__;
+extern double difftime (time_t __time1, time_t __time0);
 
 /* Return the `time_t' representation of TP and normalize TP.  */
 extern time_t mktime (struct tm *__tp) __THROW;
@@ -85,7 +84,7 @@ extern time_t mktime (struct tm *__tp) __THROW;
 # ifdef __REDIRECT_NTH
 extern time_t __REDIRECT_NTH (time, (time_t *__timer), __time64);
 extern double __REDIRECT_NTH (difftime, (time_t __time1, time_t __time0),
-                              __difftime64) __attribute_pure__;
+                              __difftime64);
 extern time_t __REDIRECT_NTH (mktime, (struct tm *__tp), __mktime64);
 # else
 #  define time __time64