[PATCH v5 2/4] user32: Correctly handle NULL string in GETTEXT/CBFORMAT AtoW wrapper.

[Aida Jonikienė]

From: Aida Jonikienė

Spotted in WM_GETTEXT NULL string tests.
---
 dlls/user32/winproc.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/dlls/user32/winproc.c b/dlls/user32/winproc.c
index 5678e75b4e9..1ce5c87f954 100644
--- a/dlls/user32/winproc.c
+++ b/dlls/user32/winproc.c
@@ -274,9 +274,13 @@ LRESULT WINPROC_CallProcAtoW( winproc_callback_t callback, HWND hwnd, UINT msg,
             LPSTR str = (LPSTR)lParam;
             DWORD len = wParam * sizeof(WCHAR);

-            if (!(ptr = get_buffer( buffer, sizeof(buffer), len ))) break;
+            if (!str)
+                ptr = NULL;
+            else if (!(ptr = get_buffer( buffer, sizeof(buffer), len )))
+                break;
+
             ret = callback( hwnd, msg, wParam, (LPARAM)ptr, result, arg );
-            if (wParam)
+            if (wParam && str)
             {
                 len = 0;
                 if (*result)