NdrGetUserMarshalInfo function (rpcndr.h)

Article
04/02/2021

The NdrGetUserMarshalInfo function provides additional information to wire_marshal and user_marshal helper functions.

Syntax

RPC_STATUS NdrGetUserMarshalInfo(
  unsigned long         *pFlags,
  unsigned long         InformationLevel,
  NDR_USER_MARSHAL_INFO *pMarshalInfo
);

Parameters

pFlags

Pointer by the same name that RPC passed to the helper function.

InformationLevel

Desired level of detail to be received. Different levels imply different sets of information fields. Only level 1 is currently defined.

pMarshalInfo

Address of a memory buffer, supplied by the application, to receive the requested information. The buffer must be at least as large as the information structure indicated by InformationLevel.

Return value

Value	Meaning
RPC_S_OK	The call succeeded.
RPC_S_INVALID_ARG	At least one of the arguments was not valid.
RPC_X_INVALID_BUFFER	Current marshaling buffer was not valid.

Remarks

The NdrGetUserMarshalInfo function is called by the wire_marshal or user_marshal helper functions (provided by the application) <type>_UserSize, <type>_UserMarshal, <type>_UserUnmarshal, and <type>_UserFree to receive extra information about the state of the call. A common use for this function is to obtain the size of the marshaling buffer for the purpose of checking for end of buffer conditions. Sending incorrectly sized data is a commonly used method of breaching system security.

For a full listing of the information returned by NdrGetUserMarshalInfo, see NDR_USER_MARSHAL_INFO.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps \| UWP apps]
Minimum supported server	Windows 2000 Server [desktop apps \| UWP apps]
Target Platform	Windows
Header	rpcndr.h (include Rpc.h)
Library	Rpcrt4.lib
DLL	Rpcrt4.dll