C# Signature:

[DllImport("user32", SetLastError=true)]
private static extern int BroadcastSystemMessage(MessageBroadcastFlags flags, IntPtr lpInfo, uint Msg, IntPtr wParam, IntPtr lParam);

[DllImport("user32", SetLastError=true)]
private static extern int BroadcastSystemMessage(MessageBroadcastFlags flags, ref MessageBroadcastRecipients lpInfo, uint Msg, IntPtr wParam, IntPtr lParam);

User-Defined Types:

[Flags]
enum MessageBroadcastFlags : uint
{     
    BSF_QUERY              = 0x00000001,
    BSF_IGNORECURRENTTASK  = 0x00000002,
    BSF_FLUSHDISK          = 0x00000004,
    BSF_NOHANG             = 0x00000008,
    BSF_POSTMESSAGE        = 0x00000010,
    BSF_FORCEIFHUNG        = 0x00000020,
    BSF_NOTIMEOUTIFNOTHUNG = 0x00000040,
    BSF_ALLOWSFW           = 0x00000080,
    BSF_SENDNOTIFYMESSAGE  = 0x00000100,
    BSF_RETURNHDESK        = 0x00000200,
    BSF_LUID               = 0x00000400
}

[Flags]
enum MessageBroadcastRecipients : uint
{
    BSM_ALLCOMPONENTS      = 0x00000000,
    BSM_VXDS               = 0x00000001,
    BSM_NETDRIVER          = 0x00000002,
    BSM_INSTALLABLEDRIVERS = 0x00000004,
    BSM_APPLICATIONS       = 0x00000008,
    BSM_ALLDESKTOPS        = 0x00000010
}

Notes:

None.

Tips & Tricks:

Please add some!

Sample Code:

MessageBroadcastRecipients recipients = MessageBroadcastRecipients.BSM_APPLICATIONS;

BroadcastSystemMessage(
    MessageBroadcastFlags.BSF_IGNORECURRENTTASK, // do not send message to this process
    ref recipients, // broadcast only to applications
    0x1,            // registered private message
    IntPtr.Zero,    // message-specific value
    IntPtr.Zero);   // message-specific value

Alternative Managed API:

Do you know one? Please contribute it!

Please edit this page!

Do you have...

• helpful tips or sample code to share for using this API in managed code?
• corrections to the existing content?
• variations of the signature you want to share?
• additional languages you want to include?

Select "Edit This Page" on the right hand toolbar and edit it! Or add new pages containing supporting types needed for this API (structures, delegates, and more).