Contents

messageClient

Sends a generic message to an attached client.

Declaration

virtual IOReturn messageClient(
 UInt32 messageType,
 OSObject *client, 
 void *messageArgument = 0,
 vm_size_t argSize = 0 );

Parameters

  • messageType:

    A type defined in IOMessage.h or defined by the provider family.

  • client:

    A client of the IOService to send the message.

  • messageArgument:

    An argument defined by the provider family, not used by IOService.

  • argSize:

    Specifies the size of messageArgument, in bytes. If argSize is non-zero, messageArgument is treated as a pointer to argSize bytes of data. If argSize is 0 (the default), messageArgument is treated as an ordinal and passed by value.

Return Value

The return code from the client message call.

Overview

A provider may deliver messages via the message method to its clients informing them of state changes, such as kIOMessageServiceIsTerminated or kIOMessageServiceIsSuspended. Certain messages are defined by the I/O Kit in IOMessage.h while others may be family dependent. This method may be called in the provider to send a message to the specified client, which may be useful for overrides.

See Also

Miscellaneous