Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
+.ad l
.sp
.BR asctime_r (),
.BR ctime_r (),
.BR gmtime_r (),
.BR localtime_r ():
-.br
+.RS
_POSIX_C_SOURCE\ >=\ 1 || _XOPEN_SOURCE || _BSD_SOURCE ||
_SVID_SOURCE || _POSIX_SOURCE
+.RE
+.ad
.SH DESCRIPTION
The
.BR ctime (),
The
.BR localtime ()
function converts the calendar time \fItimep\fP to
-broken-time representation, expressed relative to the user's specified
-timezone.
+broken-down time representation,
+expressed relative to the user's specified timezone.
The function acts as if it called
.BR tzset (3)
and sets the external variables \fItzname\fP with
If the specified broken-down
time cannot be represented as calendar time (seconds since the Epoch),
.BR mktime ()
-returns a value of
+returns
.I (time_t)\ \-1
and does not alter the
members of the broken-down time structure.