BroadcastSystemMessage

[Now Supported on Windows NT]

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.

Remarks

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