G::ReadWrite Class Reference

An abstract interface for reading and writing from a non-blocking i/o channel. More...

#include <greadwrite.h>

Inheritance diagram for G::ReadWrite:

Public Types
using	size_type = std::size_t
using	ssize_type = ssize_t

Public Member Functions
virtual ssize_type	read (char *buffer, size_type buffer_length)=0
	Reads data. More...
virtual ssize_type	write (const char *buf, size_type len)=0
	Sends data. More...
virtual bool	eWouldBlock () const =0
	See read() and write(). More...
virtual SOCKET	fd () const noexcept=0
	Returns the file descriptor. More...
virtual	~ReadWrite ()=default
	Destructor.

Detailed Description

An abstract interface for reading and writing from a non-blocking i/o channel.

Eg:

ssize_t rc = s.read( buffer , buffer.size() ) ;
if( rc == 0 ) throw Disconnected() ;
else if( rc < 0 && !s.eWouldBlock() ) throw ReadError() ;
else if( rc > 0 ) got_some( buffer , rc ) ;
else /*nothing-to-do*/ ;
 
ssize_t rc = s.write( buffer , buffer.size() )
if( rc < 0 && !s.eWouldBlock() ) throw Disconnected() ;
else if( rc < 0 || rc < buffer.size() ) sent_some( rc < 0 ? 0 : rc ) ;
else sent_all() ;

Definition at line 49 of file greadwrite.h.

Member Typedef Documentation

size_type

using G::ReadWrite::size_type = std::size_t

Definition at line 52 of file greadwrite.h.

ssize_type

using G::ReadWrite::ssize_type = ssize_t

Definition at line 53 of file greadwrite.h.

Member Function Documentation

eWouldBlock()

virtual bool G::ReadWrite::eWouldBlock ( ) const

pure virtual

See read() and write().

Implemented in GNet::SocketBase.

fd()

virtual SOCKET G::ReadWrite::fd ( ) const

pure virtualnoexcept

Returns the file descriptor.

Implemented in GNet::SocketBase.

read()

virtual ssize_type G::ReadWrite::read ( char *  buffer, size_type  buffer_length  )

pure virtual

Reads data.

Returns 0 if the connection has been lost. Returns -1 on error or if there is nothing to read (in which case eWouldBlock() returns true).

Implemented in GNet::StreamSocket, GNet::RawSocket, and GNet::DatagramSocket.

write()

virtual ssize_type G::ReadWrite::write ( const char *  buf, size_type  len  )

pure virtual

Sends data.

Returns the amount of data sent.

If this method returns -1 then use eWouldBlock() to determine whether there was a flow control problem; if it returns -1 and eWouldBlock() returns false then the connection is lost. If it returns less than the requested length then eWouldBlock() should not be used.

Implemented in GNet::StreamSocket, GNet::RawSocket, and GNet::DatagramSocket.

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

• /tmp/slackdce/slackrepo.HKsbdz/build_emailrelay/emailrelay-2.6/src/glib/greadwrite.h