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WsGetMappedHeader function

Finds a mapped header in the message and deserializes it.


HRESULT WINAPI  WsGetMappedHeader(
  _In_     WS_MESSAGE*                message,
  _In_     const WS_XML_STRING*       headerName,
  _In_     WS_REPEATING_HEADER_OPTION repeatingOption,
  _In_     ULONG                      headerIndex,
  _In_     WS_TYPE                    valueType,
  _In_     WS_READ_OPTION             readOption,
  _In_opt_ WS_HEAP*                   heap,
           void*                      value,
  _In_     ULONG                      valueSize,
  _In_opt_ WS_ERROR*                  error


message [in]

The message containing the header.

The message can be in any state but WS_MESSAGE_STATE_EMPTY.

headerName [in]

The name of the mapped header.

repeatingOption [in]

Whether the header may appear more than once in the message.

If WS_REPEATING_HEADER is used, then the header index indicates which of the headers with the specified headerName to return.

If WS_SINGLETON_HEADER is used, then the headerIndex must be zero.

headerIndex [in]

The zero-based index of the header within the set of headers with the specified headerName.

valueType [in]

The type of value to deserialize.

readOption [in]

Whether the value is required, and how to allocate the value. See WS_READ_OPTION for more information.

If the header is optional (may appear zero or one times), then WS_READ_OPTIONAL_POINTER can be used.

heap [in, optional]

The heap to store the deserialized header data in. If this is NULL, then the message heap will be used.


The interpretation of this parameter depends on the WS_READ_OPTION.

valueSize [in]

The interpretation of this parameter depends on the WS_READ_OPTION.

error [in, optional]

Specifies where additional error information should be stored if the function fails.

Return value

This function can return one of these values.

Return codeDescription

The header does not exist, and is required.

The input data was not in the expected format.

WS_SINGLETON_HEADER was specified, and there are multiple instances of the header with the specified name in the message.


There size quota of the heap was exceeded.


There was not enough memory available to deserialize the header.


One or more of the parameters are incorrect.

Other Errors

This function may return other errors not listed above.



A message may contain additional transport-specific information that is not part of the message envelope. This transport-specific information can be exposed programmatically as headers of the Message object. This function is used to read a header that has been mapped by a transport into the message.

When using the HTTP channel, the required mappings must be specified before headers can be extracted with this function. For more information, see WS_HTTP_MESSAGE_MAPPING.


Minimum supported client

Windows 7 [desktop apps | UWP apps]

Minimum supported server

Windows Server 2008 R2 [desktop apps | UWP apps]









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