user32: Fix the DDE service formatting for 64-bit.

dlls/user32/dde_misc.c

@@ -1647,7 +1647,7 @@ HGLOBAL WDML_DataHandle2Global(HDDEDATA hDdeData, BOOL fResponse, BOOL fRelease,
  */
 WDML_SERVER*	WDML_AddServer(WDML_INSTANCE* pInstance, HSZ hszService, HSZ hszTopic)
 {
-    static const WCHAR fmtW[] = {'%','s','(','0','x','%','0','8','l','x',')',0};
+    static const WCHAR fmtW[] = {'%','s','(','0','x','%','*','x',')',0};
     WDML_SERVER* 	pServer;
     WCHAR		buf1[256];
     WCHAR		buf2[256];
@@ -1659,7 +1659,7 @@ WDML_SERVER*	WDML_AddServer(WDML_INSTANCE* pInstance, HSZ hszService, HSZ hszTop
     WDML_IncHSZ(pInstance, hszService);
 
     DdeQueryStringW(pInstance->instanceID, hszService, buf1, 256, CP_WINUNICODE);
-    snprintfW(buf2, 256, fmtW, buf1, GetCurrentProcessId());
+    snprintfW(buf2, 256, fmtW, buf1, 2*sizeof(ULONG_PTR), GetCurrentProcessId());
     pServer->hszServiceSpec = DdeCreateStringHandleW(pInstance->instanceID, buf2, CP_WINUNICODE);
 
     pServer->atomService = WDML_MakeAtomFromHsz(pServer->hszService);

dlls/user32/tests/dde.c

@@ -585,7 +585,7 @@ static HDDEDATA CALLBACK server_ddeml_callback(UINT uType, UINT uFmt, HCONV hcon
         size = DdeQueryStringA(server_pid, hsz2, str, MAX_PATH, CP_WINANSI);
         ok(!strncmp(str, "TestDDEServer(", 14), "Expected TestDDEServer(, got %s\n", str);
         ok(str[size - 1] == ')', "Expected ')', got %c\n", str[size - 1]);
-        ok(size == 25, "Expected 25, got %d\n", size);
+        ok(size == 17 + 2*sizeof(ULONG_PTR), "Got size %d for %s\n", size, str);
 
         return (HDDEDATA)TRUE;
     }