Add warning under NOTES that asctime(), ctime(), gmtime(), and

localtime() may each overwrite the static object returned by any
of the other calls.

man3/ctime.3

@@ -30,7 +30,7 @@
 .\" Modified 2001-12-13, joey, aeb
 .\" Modified 2004-11-16, mtk
 .\"
-.TH CTIME 3  2007-07-26 "" "Linux Programmer's Manual"
+.TH CTIME 3  2008-04-06 "" "Linux Programmer's Manual"
 .SH NAME
 asctime, ctime, gmtime, localtime, mktime, asctime_r, ctime_r, gmtime_r,
 localtime_r \- transform date and time to broken-down time or ASCII
@@ -266,10 +266,22 @@ Thread-safe versions
 and
 .BR localtime_r ()
 are specified by SUSv2, and available since libc 5.2.5.
+
+POSIX.1-2001 says:
+"The
+.BR asctime (),
+.BR ctime (),
+.BR gmtime (),
+and
+.BR localtime ()
+functions shall return values in one of two static objects:
+a broken-down time structure and an array of type
+.IR char .
+Execution of any of the functions may overwrite the information returned
+in either of these objects by any of the other functions."
+This can occur in the glibc implementation.
 .LP
-In many implementations, including
-.IR glibc ,
-a 0 in
+In many implementations, including glibc, a 0 in
 .I tm_mday
 is interpreted as meaning the last day of the preceding month.
 .LP