Index: uspace/lib/c/generic/io/printf_core.c
===================================================================
--- uspace/lib/c/generic/io/printf_core.c	(revision 2166728911012eaec91ede11a4cebdac0ba5a81a)
+++ uspace/lib/c/generic/io/printf_core.c	(revision 368ee04b0543abf978947ce5a1ea47698bb9692f)
@@ -1448,7 +1448,13 @@
 			
 			switch (uc) {
-			/** @todo Unimplemented qualifiers:
-			 *        t ptrdiff_t - ISO C 99
-			 */
+			case 't':
+				/* ptrdiff_t */
+				if (sizeof(ptrdiff_t) == sizeof(int32_t))
+					qualifier = PrintfQualifierInt;
+				else
+					qualifier = PrintfQualifierLongLong;
+				i = nxt;
+				uc = str_decode(fmt, &nxt, STR_NO_LIMIT);
+				break;
 			case 'h':
 				/* Char or short */