diff --git a/lib/libc/stdtime/strftime.c b/lib/libc/stdtime/strftime.c
--- a/lib/libc/stdtime/strftime.c
+++ b/lib/libc/stdtime/strftime.c
@@ -319,10 +319,10 @@
 					tm = *t;
 					mkt = mktime(&tm);
 					if (TYPE_SIGNED(time_t))
-						(void) sprintf_l(buf, loc, "%ld",
-							(long) mkt);
-					else	(void) sprintf_l(buf, loc, "%lu",
-							(unsigned long) mkt);
+						(void) sprintf_l(buf, loc, "%lld",
+							(long long) mkt);
+					else	(void) sprintf_l(buf, loc, "%llu",
+							(unsigned long long) mkt);
 					pt = _add(buf, pt, ptlim);
 				}
 				continue;