I wish to implement IPC using Named Shared Memory.
To do this, one of the steps is getting a handle to a Mapping Memory Object, using CreateFileMapping().
I do it exactly as MSDN website reccommends: http://msdn.microsoft.com/en-us/library/aa366551(v=VS.85).aspx:
hFileMappingHandle = CreateFileMapping
(
INVALID_HANDLE_VALUE, // use paging file
NULL, // default security
PAGE_READWRITE, // read/write access
0, // maximum object size (high-order DWORD)
256, // maximum object size (low-order DWORD)
"Global\\MyFileMappingObject" // name of mapping object
);
DWORD dwError = GetLastError();
However, the handle returned is always 0x0, and the System Error Code returned is: 0x5 (Access Denied.)
Does anybody have the same experience, and a way to fix it, please? I use MSDN site as my reference, so I to not think, there is problem in the code.
Looks like you don't have enough privileges.
From MSDN:
Creating a file mapping object in the global namespace from a session other than session zero requires the SeCreateGlobalPrivilege privilege. For more information, see Kernel Object Namespaces.
...
The creation of a file-mapping object in the global namespace, by using CreateFileMapping, from a session other than session zero is a privileged operation. Because of this, an application running in an arbitrary Remote Desktop Session Host (RD Session Host) server session must have SeCreateGlobalPrivilege enabled in order to create a file-mapping object in the global namespace successfully. The privilege check is limited to the creation of file-mapping objects, and does not apply to opening existing ones. For example, if a service or the system creates a file-mapping object, any process running in any session can access that file-mapping object provided that the user has the necessary access.