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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:

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Collaboration diagram for ACE_Asynch_Read_File:

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List of all members.

Public Methods

 ACE_Asynch_Read_File (void)
 A do nothing constructor.

virtual ~ACE_Asynch_Read_File (void)
 Destructor.

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_Implimplementation (void) const
 Return the underlying implementation class.


Protected Methods

void implementation (ACE_Asynch_Read_File_Impl *implementation)
 Set the implementation class.


Protected Attributes

ACE_Asynch_Read_File_Implimplementation_

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.


Constructor & Destructor Documentation

ACE_Asynch_Read_File::ACE_Asynch_Read_File void   
 

A do nothing constructor.

ACE_Asynch_Read_File::~ACE_Asynch_Read_File void    [virtual]
 

Destructor.


Member Function Documentation

void ACE_Asynch_Read_File::implementation ACE_Asynch_Read_File_Impl   implementation [protected]
 

Set the implementation class.

ACE_Asynch_Read_File_Impl * ACE_Asynch_Read_File::implementation void    const
 

Return the underlying implementation class.

Reimplemented from ACE_Asynch_Read_Stream.

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.

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.

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


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.


The documentation for this class was generated from the following files:
Generated on Wed Jan 14 22:41:20 2004 for ACE by doxygen1.2.18