msvcrt: Implement %R format for strftime.

dlls/msvcrt/tests/time.c

@@ -609,6 +609,11 @@ static void test_strftime(void)
     ok(gmt_tm != NULL, "gmtime failed\n");
 
     errno = 0xdeadbeef;
+    retA = p_strftime(bufA, 256, "%R", gmt_tm);
+    ok(retA == 0, "expected 0, got %ld\n", retA);
+    ok(errno==EINVAL || broken(errno==0xdeadbeef), "errno = %d\n", errno);
+
+    errno = 0xdeadbeef;
     retA = p_strftime(bufA, 256, "%T", gmt_tm);
     ok(retA == 0, "expected 0, got %ld\n", retA);
     ok(errno==EINVAL || broken(errno==0xdeadbeef), "errno = %d\n", errno);

dlls/msvcrt/time.c

@@ -1189,6 +1189,16 @@ static MSVCRT_size_t strftime_helper(char *str, MSVCRT_size_t max, const char *f
                         time_data->str.names.am : time_data->str.names.pm))
                 return 0;
             break;
+#if _MSVCR_VER>=140
+        case 'R':
+            if(!strftime_int(str, &ret, max, mstm->tm_hour, alternate ? 0 : 2, 0, 23))
+                return 0;
+            if(ret < max)
+                str[ret++] = ':';
+            if(!strftime_int(str, &ret, max, mstm->tm_min, alternate ? 0 : 2, 0, 59))
+                return 0;
+            break;
+#endif
         case 'S':
             if(!strftime_int(str, &ret, max, mstm->tm_sec, alternate ? 0 : 2, 0, 59))
                 return 0;

dlls/ucrtbase/tests/misc.c

@@ -895,6 +895,14 @@ static void test_strftime(void)
     char bufA[256];
     size_t retA;
 
+    retA = p_strftime(bufA, sizeof(bufA), "%R", &epoch);
+    ok(retA == 5, "expected 5, got %d\n", (int)retA);
+    ok(!strcmp(bufA, "00:00"), "got %s\n", bufA);
+
+    retA = p_strftime(bufA, sizeof(bufA), "%#R", &epoch);
+    ok(retA == 3, "expected 3, got %d\n", (int)retA);
+    ok(!strcmp(bufA, "0:0"), "got %s\n", bufA);
+
     retA = p_strftime(bufA, sizeof(bufA), "%T", &epoch);
     ok(retA == 8, "expected 8, got %d\n", (int)retA);
     ok(!strcmp(bufA, "00:00:00"), "got %s\n", bufA);