ctime: do not use static struct tm buffer

[uclinux-h8/uClibc.git] / libc / misc / time / time.c

diff --git a/libc/misc/time/time.c b/libc/misc/time/time.c
index 583c17a..dfa8c0d 100644 (file)
--- a/libc/misc/time/time.c
+++ b/libc/misc/time/time.c
@@ -274,7 +274,7 @@ libc_hidden_def(asctime)
  * If we take the implicit assumption as given, then the implementation below
  * is still incorrect for tm_year values < -900, as there will be either
  * 0-padding and/or a missing negative sign for the year conversion .  But given
- * the ususal use of asctime(), I think it isn't unreasonable to restrict correct
+ * the usual use of asctime(), I think it isn't unreasonable to restrict correct
  * operation to the domain of years between 1000 and 9999.
  */
 
@@ -465,8 +465,22 @@ clock_t clock(void)
 
 char *ctime(const time_t *t)
 {
-       /* ANSI/ISO/SUSv3 say that ctime is equivalent to the following. */
-       return asctime(localtime(t));
+       /* ANSI/ISO/SUSv3 say that ctime is equivalent to the following:
+        * return asctime(localtime(t));
+        * I don't think "equivalent" means "it uses the same internal buffer",
+        * it means "gives the same resultant string".
+        *
+        * I doubt anyone ever uses weird code like:
+        * struct tm *ptm = localtime(t1); ...; ctime(t2); use(ptm);
+        * which relies on the assumption that ctime's and localtime's
+        * internal static struct tm is the same.
+        *
+        * Using localtime_r instead of localtime avoids linking in
+        * localtime's static buffer:
+        */
+       struct tm xtm;
+
+       return asctime(localtime_r(t, &xtm));
 }
 libc_hidden_def(ctime)
 #endif