ACE_Stream_Head<> Class Template Reference

Standard task that acts as reader or writer at the head of an ACE_Stream. More...

#include <Stream_Modules.h>

Inheritance diagram for ACE_Stream_Head<>:

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Collaboration diagram for ACE_Stream_Head<>:

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List of all members.

Public Member Functions
	ACE_Stream_Head (void)
	Construction.
	~ACE_Stream_Head (void)
	Destruction.
virtual int	open (void *a=0)
virtual int	close (u_long flags=0)
virtual int	put (ACE_Message_Block *msg, ACE_Time_Value *=0)
virtual int	svc (void)
	Run by a daemon thread to handle deferred processing.
virtual int	init (int argc, ACE_TCHAR *argv[])
	Initializes object when dynamic linking occurs.
virtual int	info (ACE_TCHAR **info_string, size_t length) const
	Returns information on a service object.
virtual int	fini (void)
	Terminates object when dynamic unlinking occurs.
void	dump (void) const
	Dump the state of an object.
Public Attributes
	ACE_ALLOC_HOOK_DECLARE
	Declare the dynamic allocation hooks.
Private Member Functions
int	control (ACE_Message_Block *)
	Performs canonical flushing at the ACE_Stream Head.
int	canonical_flush (ACE_Message_Block *)

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Detailed Description

template<ACE_SYNCH_DECL>
class ACE_Stream_Head<>

Standard task that acts as reader or writer at the head of an ACE_Stream.

A ACE_Message_Block sent to this task (via its put() hook) triggers actions depending on the block type and whether the task is acting as a reader or a writer. If the block is of type ACE_Message_Block::MB_IOCTL, the block's is assumed to contain (beginning at its rd_ptr()) an ACE_IO_Cntl_Msg object and is processed accordingly. This is usually used to set the task's message queue high water and/or low water marks.

When the block is not ACE_Message_Block::MB_IOCTL, processing depends on the ACE_Stream_Head's role in the module:

• Reader: If the block is of type ACE_Message_Block::MB_FLUSH, the canonical_flush() method is called. (

  See also:

  ACE_Stream::canonical_flush().) If the block is any other type, it is queued on this task's message queue. It would thus be available to caller's reading blocks from the containing stream.

• Writer: The block is passed to the next module in the stream.

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Constructor & Destructor Documentation

template<ACE_SYNCH_DECL >

ACE_BEGIN_VERSIONED_NAMESPACE_DECL ACE_Stream_Head<>::ACE_Stream_Head

(

void

)

[inline]

Construction.

template<ACE_SYNCH_DECL >

ACE_Stream_Head<>::~ACE_Stream_Head

(

void

)

[inline]

Destruction.

---

Member Function Documentation

template<ACE_SYNCH_DECL >

int ACE_Stream_Head<>::open

(

void *

args = 0

)

[inline, virtual]

Hook called to initialize a task and prepare it for execution. args can be used to pass arbitrary information into <open>.

Reimplemented from ACE_Task_Base.

template<ACE_SYNCH_DECL >

int ACE_Stream_Head<>::close

(

u_long

flags = 0

)

[inline, virtual]

Hook called from ACE_Thread_Exit when during thread exit and from the default implementation of <module_closed>. In general, this method shouldn't be called directly by an application, particularly if the <Task> is running as an Active Object. Instead, a special message should be passed into the <Task> via the <put> method defined below, and the <svc> method should interpret this as a flag to shut down the <Task>.

Reimplemented from ACE_Task_Base.

template<ACE_SYNCH_DECL >

int ACE_Stream_Head<>::put	(	ACE_Message_Block *	,
		ACE_Time_Value *	= 0
	)			[inline, virtual]

A hook method that can be used to pass a message to a task, where it can be processed immediately or queued for subsequent processing in the <svc> hook method.

Reimplemented from ACE_Task_Base.

template<ACE_SYNCH_DECL >

int ACE_Stream_Head<>::svc

(

void

)

[inline, virtual]

Run by a daemon thread to handle deferred processing.

Reimplemented from ACE_Task_Base.

template<ACE_SYNCH_DECL >

int ACE_Stream_Head<>::init	(	int	argc,
		ACE_TCHAR *	argv[]
	)			[inline, virtual]

Initializes object when dynamic linking occurs.

Reimplemented from ACE_Shared_Object.

template<ACE_SYNCH_DECL >

int ACE_Stream_Head<>::info	(	ACE_TCHAR **	info_string,
		size_t	length
	)			const [inline, virtual]

Returns information on a service object.

Reimplemented from ACE_Shared_Object.

template<ACE_SYNCH_DECL >

int ACE_Stream_Head<>::fini

(

void

)

[inline, virtual]

Terminates object when dynamic unlinking occurs.

Reimplemented from ACE_Shared_Object.

template<ACE_SYNCH_DECL >

void ACE_Stream_Head<>::dump

(

void

)

const [inline]

Dump the state of an object.

Reimplemented from ACE_Task< ACE_SYNCH_USE >.

template<ACE_SYNCH_DECL >

int ACE_Stream_Head<>::control

(

ACE_Message_Block *

mb

)

[inline, private]

Performs canonical flushing at the ACE_Stream Head.

template<ACE_SYNCH_DECL >

int ACE_Stream_Head<>::canonical_flush

(

ACE_Message_Block *

mb

)

[inline, private]

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Member Data Documentation

template<ACE_SYNCH_DECL >

ACE_Stream_Head<>::ACE_ALLOC_HOOK_DECLARE

Declare the dynamic allocation hooks.

Reimplemented from ACE_Task< ACE_SYNCH_USE >.

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The documentation for this class was generated from the following files:

• Stream_Modules.h
• Stream_Modules.cpp