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ACE_Asynch_Read_File Class Reference

This class is a factory for starting off asynchronous reads on a file. This class forwards all methods to its implementation class. More...

#include <Asynch_IO.h>

Inheritance diagram for ACE_Asynch_Read_File:

[legend]Collaboration diagram for ACE_Asynch_Read_File:

[legend]List of all members.

Public Methods
	ACE_Asynch_Read_File (void)
	A do nothing constructor. More...
virtual	~ACE_Asynch_Read_File (void)
	Destructor. More...
int	open (ACE_Handler &handler, ACE_HANDLE handle=ACE_INVALID_HANDLE, const void *completion_key=0, ACE_Proactor *proactor=0)
int	read (ACE_Message_Block &message_block, size_t bytes_to_read, u_long offset=0, u_long offset_high=0, const void *act=0, int priority=0, int signal_number=ACE_SIGRTMIN)
int	readv (ACE_Message_Block &message_block, size_t bytes_to_read, u_long offset=0, u_long offset_high=0, const void *act=0, int priority=0, int signal_number=ACE_SIGRTMIN)
ACE_Asynch_Read_File_Impl *	implementation (void) const
	Return the underlying implementation class. More...
Protected Methods
void	implementation (ACE_Asynch_Read_File_Impl *implementation)
	Set the implementation class. More...
Protected Attributes
ACE_Asynch_Read_File_Impl *	implementation_
	Delegation/implementation class that all methods will be forwarded to. More...

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Detailed Description

This class is a factory for starting off asynchronous reads on a file. This class forwards all methods to its implementation class.

Once <open> is called, multiple asynchronous <read>s can started using this class. An ACE_Asynch_Read_File::Result will be passed back to the <handler> when the asynchronous reads completes through the <ACE_Handler::handle_read_file> callback. This class differs slightly from ACE_Asynch_Read_Stream as it allows the user to specify an offset for the read.

Definition at line 510 of file Asynch_IO.h.

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Constructor & Destructor Documentation

ACE_Asynch_Read_File::ACE_Asynch_Read_File (  void    )

A do nothing constructor. Definition at line 402 of file Asynch_IO.cpp. References ACE_Asynch_Write_Stream::implementation_. : implementation_ (0) { }

ACE_Asynch_Read_File::~ACE_Asynch_Read_File (  void    )  [virtual]

Destructor. Definition at line 407 of file Asynch_IO.cpp. { }

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Member Function Documentation

void ACE_Asynch_Read_File::implementation (  ACE_Asynch_Read_File_Impl *    implementation )  [protected]

Set the implementation class. Definition at line 484 of file Asynch_IO.cpp. References ACE_Asynch_Read_Stream::implementation, and implementation_. { this->implementation_ = implementation; // Set also the base class' implementation. ACE_Asynch_Read_Stream::implementation (implementation); }

ACE_Asynch_Read_File_Impl * ACE_Asynch_Read_File::implementation (  void    )  const

Return the underlying implementation class. Reimplemented from ACE_Asynch_Read_Stream. Definition at line 478 of file Asynch_IO.cpp. References implementation_. Referenced by open, read, and readv. { return this->implementation_; }

int ACE_Asynch_Read_File::open (  ACE_Handler &    handler, ACE_HANDLE    handle = ACE_INVALID_HANDLE, const void *    completion_key = 0, ACE_Proactor *    proactor = 0 )

Initializes the factory with information which will be used with each asynchronous call. If (<handle> == ACE_INVALID_HANDLE), <ACE_Handler::handle> will be called on the <handler> to get the correct handle. Reimplemented from ACE_Asynch_Read_Stream. Definition at line 412 of file Asynch_IO.cpp. References ACE_Proactor::create_asynch_read_file, ACE_Asynch_Operation::get_proactor, implementation, implementation_, and ACE_Asynch_Operation::open. { // Get a proactor for/from the user. proactor = this->get_proactor (proactor, handler); // Delete the old implementation. delete this->implementation_; this->implementation_ = 0; // Now let us get the implementation initialized. ACE_Asynch_Read_File_Impl *implementation = proactor->create_asynch_read_file (); if (implementation == 0) return -1; // Set the implementation class this->implementation (implementation); // Call the <open> method of the base class. return ACE_Asynch_Operation::open (handler, handle, completion_key, proactor); }

int ACE_Asynch_Read_File::read (  ACE_Message_Block &    message_block, size_t    bytes_to_read, u_long    offset = 0, u_long    offset_high = 0, const void *    act = 0, int    priority = 0, int    signal_number = ACE_SIGRTMIN )

This starts off an asynchronous read. Upto <bytes_to_read> will be read and stored in the <message_block>. The read will start at <offset> from the beginning of the file. Priority of the operation is specified by <priority>. On POSIX4-Unix, this is supported. Works like <nice> in Unix. Negative values are not allowed. 0 means priority of the operation same as the process priority. 1 means priority of the operation is one less than process. And so forth. On Win32, this argument is a no-op. <signal_number> is the POSIX4 real-time signal number to be used for the operation. <signal_number> ranges from ACE_SIGRTMIN to ACE_SIGRTMAX. This argument is a no-op on non-POSIX4 systems. Definition at line 440 of file Asynch_IO.cpp. References implementation, and ACE_Asynch_Read_File_Impl::read. { return this->implementation ()->read (message_block, bytes_to_read, offset, offset_high, act, priority, signal_number); }

int ACE_Asynch_Read_File::readv (  ACE_Message_Block &    message_block, size_t    bytes_to_read, u_long    offset = 0, u_long    offset_high = 0, const void *    act = 0, int    priority = 0, int    signal_number = ACE_SIGRTMIN )

Same as above but with scatter support, through chaining of composite message blocks using the continuation field. NOTE: In win32 Each data block payload must be at least the size of a system memory page and must be aligned on a system memory page size boundary Definition at line 459 of file Asynch_IO.cpp. References implementation, and ACE_Asynch_Read_File_Impl::readv. { return this->implementation ()->readv (message_block, bytes_to_read, offset, offset_high, act, priority, signal_number); }

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Member Data Documentation

ACE_Asynch_Read_File_Impl* ACE_Asynch_Read_File::implementation_ [protected]

Delegation/implementation class that all methods will be forwarded to. Reimplemented from ACE_Asynch_Read_Stream. Definition at line 577 of file Asynch_IO.h. Referenced by ACE_Asynch_Write_File::ACE_Asynch_Write_File, implementation, and open.

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

• Asynch_IO.h
• Asynch_IO.cpp

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