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BroadcastSystemMessage info  Overview  Group

The BroadcastSystemMessage function sends a message to the specified recipients. The recipients can be applications, installable drivers, Windows-based network drivers, system-level device drivers, or any combination of these system components.

long BroadcastSystemMessage(

    DWORD dwFlags, 

    LPDWORD lpdwRecipients, 

    UINT uiMessage, 

    WPARAM wParam, 

    LPARAM lParam 

   );

Parameters

dwFlags
Option flags. Can be a combination of the following values:

Value

Meaning

BSF_FLUSHDISK

Flush the disk after each recipient processes the message.

BSF_FORCEIFHUNG

Continue to broadcast the message, even if the time-out period elapses or one of the recipients is hung..

BSF_IGNORECURRENTTASK

Do not send the message to windows that belong to the current task. This prevents an application from receiving its own message.

BSF_NOHANG

Force a hung application to time out. If one of the recipients times out, do not continue broadcasting the message.

BSF_NOTIMEOUTIFNOTHUNG

Wait for a response to the message, as long as the recipient is not hung. Do not time out.

BSF_POSTMESSAGE

Post the message. Do not use in combination with BSF_QUERY.

BSF_QUERY

Send the message to one recipient at a time, sending to a subsequent recipient only if the current recipient returns TRUE.

lpdwRecipients
Pointer to a variable that contains and receives information about the recipients of the message. The variable can be a combination of the following values:

Value

Meaning

BSM_ALLCOMPONENTS

Broadcast to all system components.

BSM_ALLDESKTOPS

Windows NT only: Broadcast to all desktops. Requires the SE_TCB_NAME privilege.

BSM_APPLICATIONS

Broadcast to applications.

BSM_INSTALLABLEDRIVERS

Windows 95: Broadcast to installable drivers.

Windows NT: This value is not meaningful.

BSM_NETDRIVER

Windows 95: Broadcast to Windows-based network drivers.

Windows NT: This value is not meaningful.

BSM_VXDS

Windows 95: Broadcast to all system-level device drivers.

Windows NT: This value is not meaningful.

When the function returns, this variable receives a combination of these values identifying which recipients actually received the message.

If this parameter is NULL, the function broadcasts to all components.

uiMessage
Identifier of the system message.
wParam
32-bit message-specific value.
lParam
32-bit message-specific value.

Return Values

If the function succeeds, the return value is a positive value.

If the function is unable to broadcast the message, the return value is -1.

If the dwFlags parameter is BSF_QUERY and at least one recipient returned BROADCAST_QUERY_DENY to the corresponding message, the return value is zero. To get extended error information, call GetLastError.

Remarks

If BSF_QUERY is not specified, the function sends the specified message to all requested recipients, ignoring values returned by those recipients.

See:

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