[PATCH] localspl: Clear lasterror on success in AddMonitor, with test

[Detlef Riekenberg]

This is ugly, but there are printmonitor installers,
which depend on GetLastError() even on success of AddMonitor

redmon is an example:
https://bugs.winehq.org/show_bug.cgi?id=3864#c22

Many Monitors depend on the example code from Microsoft, so...

--
bye bye ... Detlef

Signed-off-by: Detlef Riekenberg <wine.dev at web.de>
---
 dlls/localspl/provider.c       | 3 +++
 dlls/winspool.drv/tests/info.c | 6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/dlls/localspl/provider.c b/dlls/localspl/provider.c
index f359b73..f370b9f 100644
--- a/dlls/localspl/provider.c
+++ b/dlls/localspl/provider.c
@@ -1541,6 +1541,9 @@ static BOOL WINAPI fpAddMonitor(LPWSTR pName, DWORD Level, LPBYTE pMonitors)
         RegCloseKey(hentry);
     }
 
+    if (res)
+        SetLastError(ERROR_SUCCESS); /* Monitor installer depend on this */
+
     RegCloseKey(hroot);
     return (res);
 }
diff --git a/dlls/winspool.drv/tests/info.c b/dlls/winspool.drv/tests/info.c
index f6527c5..602e935 100644
--- a/dlls/winspool.drv/tests/info.c
+++ b/dlls/winspool.drv/tests/info.c
@@ -435,6 +435,12 @@ static void test_AddMonitor(void)
     SetLastError(MAGIC_DEAD);
     res = AddMonitorA(NULL, 2, (LPBYTE) &mi2a);
     ok(res, "returned %d with %d (expected '!= 0')\n", res, GetLastError());
+    if (res)
+    {
+        /* Some apps depend on the result of GetLastError() */
+        res = GetLastError();
+        ok(res == ERROR_SUCCESS, "got 0x%x/%u (expected ERROR_SUCCESS)\n", res, res);
+    }
 
     /* add a monitor twice */
     SetLastError(MAGIC_DEAD);
-- 
2.7.4