GetMenuItemInfo access violation in user32.dll

[jphillips_2003]

when accessing from another thread.

void getMenuItem(HWND hWndMenu)
{
HMENU menu = GetMenu(hWndMenu);
MENUITEMINFO mi, *_mi; unsigned long pid;
HANDLE process;

GetWindowThreadProcessId(hWndMenu, &pid);
process=OpenProcess (PROCESS_VM_OPERATION|PROCESS_VM_READ|PROCESS_VM_WRITE|PROCESS_QUERY_INFORMATION, FALSE, pid);
_mi=(MENUITEMINFO*)VirtualAllocEx(process, NULL, sizeof(MENUITEMINFO), MEM_COMMIT, PAGE_READWRITE);

ZeroMemory(&mi, sizeof(MENUITEMINFO));

mi.cbSize = sizeof(MENUITEMINFO);
mi.fMask = MIIM_TYPE;
mi.fType = MFT_STRING;
mi.dwTypeData=NULL;
WriteProcessMemory(process, _mi, &mi, sizeof(MENUITEMINFO), NULL);
// this fails GetMenuItemInfo(menu, 1, true, _mi);
ReadProcessMemory(process, _mi, mi, sizeof(MENUITEMINFO), NULL);
int size = mi.cch;
VirtualFreeEx(process, _mi, 0, MEM_RELEASE);

[VictorN]

Are you sure all your handles (HWMD hWndMenu, HMENU menu, HANDLE process,...) are not NULL and valid?
You must check all of them before trying to use!