ACE  6.1.0
Classes | Public Member Functions | Protected Attributes | Private Member Functions
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.

Classes

class  Result
 This is that class which will be passed back to the {handler} when the asynchronous read completes. This class forwards all the methods to the implementation class. More...

Public Member Functions

 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, unsigned long offset=0, unsigned 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, unsigned long offset=0, unsigned long offset_high=0, const void *act=0, int priority=0, int signal_number=ACE_SIGRTMIN)
virtual ACE_Asynch_Operation_Implimplementation (void) const
 Return the underlying implementation class.

Protected Attributes

ACE_Asynch_Read_File_Implimplementation_

Private Member Functions

void operator= (const ACE_Asynch_Read_File &)
 ACE_Asynch_Read_File (const ACE_Asynch_Read_File &)

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 reads can started using this class. An ACE_Asynch_Read_File::Result will be passed back to the completion handler's ACE_Handler::handle_read_file() method when each asynchronous read completes. 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.

ACE_Asynch_Read_File::ACE_Asynch_Read_File ( const ACE_Asynch_Read_File ) [private]

Member Function Documentation

ACE_Asynch_Operation_Impl * ACE_Asynch_Read_File::implementation ( void  ) const [virtual]

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 operation.

Parameters:
handlerACE_Handler to be notified when operations initiated via this factory complete. The ACE_Handler::handle_read_file() method will be called on this object.
handleThe file handle to initiate read operations on. If handle is ACE_INVALID_HANDLE, ACE_Handler::handle() will be called on handler to get the handle value.
completion_keyA token that is passed to the completion handler.
proactorThe ACE_Proactor object which will control operation completion and dispatching the results to handler. If this is 0, the process's singleton ACE_Proactor will be used.
Return values:
0for success.
-1for failure; consult errno for further information.

Reimplemented from ACE_Asynch_Read_Stream.

void ACE_Asynch_Read_File::operator= ( const ACE_Asynch_Read_File ) [private]
int ACE_Asynch_Read_File::read ( ACE_Message_Block message_block,
size_t  bytes_to_read,
unsigned long  offset = 0,
unsigned 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,
unsigned long  offset = 0,
unsigned 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

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:
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