asio::read

The read function is a composed operation that reads a certain amount of data from a stream before returning. More...

Functions
template<typename SyncReadStream , typename MutableBufferSequence >
std::size_t	asio::read (SyncReadStream &s, const MutableBufferSequence &buffers, typename enable_if< is_mutable_buffer_sequence< MutableBufferSequence >::value >::type *=0)
	Attempt to read a certain amount of data from a stream before returning. More...
template<typename SyncReadStream , typename MutableBufferSequence >
std::size_t	asio::read (SyncReadStream &s, const MutableBufferSequence &buffers, asio::error_code &ec, typename enable_if< is_mutable_buffer_sequence< MutableBufferSequence >::value >::type *=0)
	Attempt to read a certain amount of data from a stream before returning. More...
template<typename SyncReadStream , typename MutableBufferSequence , typename CompletionCondition >
std::size_t	asio::read (SyncReadStream &s, const MutableBufferSequence &buffers, CompletionCondition completion_condition, typename enable_if< is_mutable_buffer_sequence< MutableBufferSequence >::value >::type *=0)
	Attempt to read a certain amount of data from a stream before returning. More...
template<typename SyncReadStream , typename MutableBufferSequence , typename CompletionCondition >
std::size_t	asio::read (SyncReadStream &s, const MutableBufferSequence &buffers, CompletionCondition completion_condition, asio::error_code &ec, typename enable_if< is_mutable_buffer_sequence< MutableBufferSequence >::value >::type *=0)
	Attempt to read a certain amount of data from a stream before returning. More...
template<typename SyncReadStream , typename DynamicBuffer_v1 >
std::size_t	asio::read (SyncReadStream &s, ASIO_MOVE_ARG(DynamicBuffer_v1) buffers, typename enable_if< is_dynamic_buffer_v1< typename decay< DynamicBuffer_v1 >::type >::value &&!is_dynamic_buffer_v2< typename decay< DynamicBuffer_v1 >::type >::value >::type *=0)
	Attempt to read a certain amount of data from a stream before returning. More...
template<typename SyncReadStream , typename DynamicBuffer_v1 >
std::size_t	asio::read (SyncReadStream &s, ASIO_MOVE_ARG(DynamicBuffer_v1) buffers, asio::error_code &ec, typename enable_if< is_dynamic_buffer_v1< typename decay< DynamicBuffer_v1 >::type >::value &&!is_dynamic_buffer_v2< typename decay< DynamicBuffer_v1 >::type >::value >::type *=0)
	Attempt to read a certain amount of data from a stream before returning. More...
template<typename SyncReadStream , typename DynamicBuffer_v1 , typename CompletionCondition >
std::size_t	asio::read (SyncReadStream &s, ASIO_MOVE_ARG(DynamicBuffer_v1) buffers, CompletionCondition completion_condition, typename enable_if< is_dynamic_buffer_v1< typename decay< DynamicBuffer_v1 >::type >::value &&!is_dynamic_buffer_v2< typename decay< DynamicBuffer_v1 >::type >::value >::type *=0)
	Attempt to read a certain amount of data from a stream before returning. More...
template<typename SyncReadStream , typename DynamicBuffer_v1 , typename CompletionCondition >
std::size_t	asio::read (SyncReadStream &s, ASIO_MOVE_ARG(DynamicBuffer_v1) buffers, CompletionCondition completion_condition, asio::error_code &ec, typename enable_if< is_dynamic_buffer_v1< typename decay< DynamicBuffer_v1 >::type >::value &&!is_dynamic_buffer_v2< typename decay< DynamicBuffer_v1 >::type >::value >::type *=0)
	Attempt to read a certain amount of data from a stream before returning. More...
template<typename SyncReadStream , typename Allocator >
std::size_t	asio::read (SyncReadStream &s, basic_streambuf< Allocator > &b)
	Attempt to read a certain amount of data from a stream before returning. More...
template<typename SyncReadStream , typename Allocator >
std::size_t	asio::read (SyncReadStream &s, basic_streambuf< Allocator > &b, asio::error_code &ec)
	Attempt to read a certain amount of data from a stream before returning. More...
template<typename SyncReadStream , typename Allocator , typename CompletionCondition >
std::size_t	asio::read (SyncReadStream &s, basic_streambuf< Allocator > &b, CompletionCondition completion_condition)
	Attempt to read a certain amount of data from a stream before returning. More...
template<typename SyncReadStream , typename Allocator , typename CompletionCondition >
std::size_t	asio::read (SyncReadStream &s, basic_streambuf< Allocator > &b, CompletionCondition completion_condition, asio::error_code &ec)
	Attempt to read a certain amount of data from a stream before returning. More...
template<typename SyncReadStream , typename DynamicBuffer_v2 >
std::size_t	asio::read (SyncReadStream &s, DynamicBuffer_v2 buffers, typename enable_if< is_dynamic_buffer_v2< DynamicBuffer_v2 >::value >::type *=0)
	Attempt to read a certain amount of data from a stream before returning. More...
template<typename SyncReadStream , typename DynamicBuffer_v2 >
std::size_t	asio::read (SyncReadStream &s, DynamicBuffer_v2 buffers, asio::error_code &ec, typename enable_if< is_dynamic_buffer_v2< DynamicBuffer_v2 >::value >::type *=0)
	Attempt to read a certain amount of data from a stream before returning. More...
template<typename SyncReadStream , typename DynamicBuffer_v2 , typename CompletionCondition >
std::size_t	asio::read (SyncReadStream &s, DynamicBuffer_v2 buffers, CompletionCondition completion_condition, typename enable_if< is_dynamic_buffer_v2< DynamicBuffer_v2 >::value >::type *=0)
	Attempt to read a certain amount of data from a stream before returning. More...
template<typename SyncReadStream , typename DynamicBuffer_v2 , typename CompletionCondition >
std::size_t	asio::read (SyncReadStream &s, DynamicBuffer_v2 buffers, CompletionCondition completion_condition, asio::error_code &ec, typename enable_if< is_dynamic_buffer_v2< DynamicBuffer_v2 >::value >::type *=0)
	Attempt to read a certain amount of data from a stream before returning. More...

Detailed Description

The read function is a composed operation that reads a certain amount of data from a stream before returning.

Function Documentation

read() [1/16]

template<typename SyncReadStream , typename MutableBufferSequence , typename CompletionCondition >

std::size_t asio::read	(	SyncReadStream &	s,
		const MutableBufferSequence &	buffers,
		CompletionCondition	completion_condition,
		asio::error_code &	ec,
		typename enable_if< is_mutable_buffer_sequence< MutableBufferSequence >::value >::type *	= 0
	)

Attempt to read a certain amount of data from a stream before returning.

This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:

• The supplied buffers are full. That is, the bytes transferred is equal to the sum of the buffer sizes.

• The completion_condition function object returns 0.

This operation is implemented in terms of zero or more calls to the stream's read_some function.

Parameters

s	The stream from which the data is to be read. The type must support the SyncReadStream concept.
buffers	One or more buffers into which the data will be read. The sum of the buffer sizes indicates the maximum number of bytes to read from the stream.
completion_condition	The function object to be called to determine whether the read operation is complete. The signature of the function object must be: std::size_t completion_condition( // Result of latest read_some operation. const asio::error_code& error, // Number of bytes transferred so far. std::size_t bytes_transferred ); A return value of 0 indicates that the read operation is complete. A non-zero return value indicates the maximum number of bytes to be read on the next call to the stream's read_some function.
ec	Set to indicate what error occurred, if any.

Returns

The number of bytes read. If an error occurs, returns the total number of bytes successfully transferred prior to the error.

read() [2/16]

template<typename SyncReadStream , typename MutableBufferSequence >

std::size_t asio::read ( SyncReadStream &  s, const MutableBufferSequence &  buffers, typename enable_if< is_mutable_buffer_sequence< MutableBufferSequence >::value >::type *  = 0  )

inline

Attempt to read a certain amount of data from a stream before returning.

This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:

• The supplied buffers are full. That is, the bytes transferred is equal to the sum of the buffer sizes.

• An error occurred.

This operation is implemented in terms of zero or more calls to the stream's read_some function.

Parameters

s	The stream from which the data is to be read. The type must support the SyncReadStream concept.
buffers	One or more buffers into which the data will be read. The sum of the buffer sizes indicates the maximum number of bytes to read from the stream.

Returns

The number of bytes transferred.

Exceptions

asio::system_error

Thrown on failure.

Example

To read into a single data buffer use the asio::buffer function as follows:

asio::read(s, asio::buffer(data, size)); 

See the asio::buffer documentation for information on reading into multiple buffers in one go, and how to use it with arrays, boost::array or std::vector.

Note

This overload is equivalent to calling:

asio::read(
   s, buffers,
   asio::transfer_all()); 

read() [3/16]

template<typename SyncReadStream , typename MutableBufferSequence >

std::size_t asio::read ( SyncReadStream &  s, const MutableBufferSequence &  buffers, asio::error_code &  ec, typename enable_if< is_mutable_buffer_sequence< MutableBufferSequence >::value >::type *  = 0  )

inline

Attempt to read a certain amount of data from a stream before returning.

This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:

• The supplied buffers are full. That is, the bytes transferred is equal to the sum of the buffer sizes.

• An error occurred.

This operation is implemented in terms of zero or more calls to the stream's read_some function.

Parameters

s	The stream from which the data is to be read. The type must support the SyncReadStream concept.
buffers	One or more buffers into which the data will be read. The sum of the buffer sizes indicates the maximum number of bytes to read from the stream.
ec	Set to indicate what error occurred, if any.

Returns

The number of bytes transferred.

Example

To read into a single data buffer use the asio::buffer function as follows:

asio::read(s, asio::buffer(data, size), ec); 

See the asio::buffer documentation for information on reading into multiple buffers in one go, and how to use it with arrays, boost::array or std::vector.

Note

This overload is equivalent to calling:

asio::read(
   s, buffers,
   asio::transfer_all(), ec); 

read() [4/16]

template<typename SyncReadStream , typename MutableBufferSequence , typename CompletionCondition >

std::size_t asio::read ( SyncReadStream &  s, const MutableBufferSequence &  buffers, CompletionCondition  completion_condition, typename enable_if< is_mutable_buffer_sequence< MutableBufferSequence >::value >::type *  = 0  )

inline

Attempt to read a certain amount of data from a stream before returning.

This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:

• The supplied buffers are full. That is, the bytes transferred is equal to the sum of the buffer sizes.

• The completion_condition function object returns 0.

This operation is implemented in terms of zero or more calls to the stream's read_some function.

Parameters

s	The stream from which the data is to be read. The type must support the SyncReadStream concept.
buffers	One or more buffers into which the data will be read. The sum of the buffer sizes indicates the maximum number of bytes to read from the stream.
completion_condition	The function object to be called to determine whether the read operation is complete. The signature of the function object must be: std::size_t completion_condition( // Result of latest read_some operation. const asio::error_code& error, // Number of bytes transferred so far. std::size_t bytes_transferred ); A return value of 0 indicates that the read operation is complete. A non-zero return value indicates the maximum number of bytes to be read on the next call to the stream's read_some function.

Returns

The number of bytes transferred.

Exceptions

asio::system_error

Thrown on failure.

Example

To read into a single data buffer use the asio::buffer function as follows:

asio::read(s, asio::buffer(data, size),
   asio::transfer_at_least(32)); 

See the asio::buffer documentation for information on reading into multiple buffers in one go, and how to use it with arrays, boost::array or std::vector.

read() [5/16]

template<typename SyncReadStream , typename DynamicBuffer_v1 , typename CompletionCondition >

std::size_t asio::read	(	SyncReadStream &	s,
		ASIO_MOVE_ARG(DynamicBuffer_v1)	buffers,
		CompletionCondition	completion_condition,
		asio::error_code &	ec,
		typename enable_if< is_dynamic_buffer_v1< typename decay< DynamicBuffer_v1 >::type >::value &&!is_dynamic_buffer_v2< typename decay< DynamicBuffer_v1 >::type >::value >::type *	= 0
	)

Attempt to read a certain amount of data from a stream before returning.

This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:

• The specified dynamic buffer sequence is full (that is, it has reached maximum size).

• The completion_condition function object returns 0.

This operation is implemented in terms of zero or more calls to the stream's read_some function.

Parameters

s	The stream from which the data is to be read. The type must support the SyncReadStream concept.
buffers	The dynamic buffer sequence into which the data will be read.
completion_condition	The function object to be called to determine whether the read operation is complete. The signature of the function object must be: std::size_t completion_condition( // Result of latest read_some operation. const asio::error_code& error, // Number of bytes transferred so far. std::size_t bytes_transferred ); A return value of 0 indicates that the read operation is complete. A non-zero return value indicates the maximum number of bytes to be read on the next call to the stream's read_some function.
ec	Set to indicate what error occurred, if any.

Returns

The number of bytes read. If an error occurs, returns the total number of bytes successfully transferred prior to the error.

read() [6/16]

template<typename SyncReadStream , typename DynamicBuffer_v1 >

std::size_t asio::read ( SyncReadStream &  s, ASIO_MOVE_ARG(DynamicBuffer_v1)  buffers, typename enable_if< is_dynamic_buffer_v1< typename decay< DynamicBuffer_v1 >::type >::value &&!is_dynamic_buffer_v2< typename decay< DynamicBuffer_v1 >::type >::value >::type *  = 0  )

inline

Attempt to read a certain amount of data from a stream before returning.

This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:

• The specified dynamic buffer sequence is full (that is, it has reached maximum size).

• An error occurred.

This operation is implemented in terms of zero or more calls to the stream's read_some function.

Parameters

s	The stream from which the data is to be read. The type must support the SyncReadStream concept.
buffers	The dynamic buffer sequence into which the data will be read.

Returns

The number of bytes transferred.

Exceptions

asio::system_error

Thrown on failure.

Note

This overload is equivalent to calling:

asio::read(
   s, buffers,
   asio::transfer_all()); 

read() [7/16]

template<typename SyncReadStream , typename DynamicBuffer_v1 >

std::size_t asio::read ( SyncReadStream &  s, ASIO_MOVE_ARG(DynamicBuffer_v1)  buffers, asio::error_code &  ec, typename enable_if< is_dynamic_buffer_v1< typename decay< DynamicBuffer_v1 >::type >::value &&!is_dynamic_buffer_v2< typename decay< DynamicBuffer_v1 >::type >::value >::type *  = 0  )

inline

Attempt to read a certain amount of data from a stream before returning.

This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:

• The supplied buffer is full (that is, it has reached maximum size).

• An error occurred.

This operation is implemented in terms of zero or more calls to the stream's read_some function.

Parameters

s	The stream from which the data is to be read. The type must support the SyncReadStream concept.
buffers	The dynamic buffer sequence into which the data will be read.
ec	Set to indicate what error occurred, if any.

Returns

The number of bytes transferred.

Note

This overload is equivalent to calling:

asio::read(
   s, buffers,
   asio::transfer_all(), ec); 

read() [8/16]

template<typename SyncReadStream , typename DynamicBuffer_v1 , typename CompletionCondition >

std::size_t asio::read ( SyncReadStream &  s, ASIO_MOVE_ARG(DynamicBuffer_v1)  buffers, CompletionCondition  completion_condition, typename enable_if< is_dynamic_buffer_v1< typename decay< DynamicBuffer_v1 >::type >::value &&!is_dynamic_buffer_v2< typename decay< DynamicBuffer_v1 >::type >::value >::type *  = 0  )

inline

Attempt to read a certain amount of data from a stream before returning.

This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:

• The specified dynamic buffer sequence is full (that is, it has reached maximum size).

• The completion_condition function object returns 0.

This operation is implemented in terms of zero or more calls to the stream's read_some function.

Parameters

s	The stream from which the data is to be read. The type must support the SyncReadStream concept.
buffers	The dynamic buffer sequence into which the data will be read.
completion_condition	The function object to be called to determine whether the read operation is complete. The signature of the function object must be: std::size_t completion_condition( // Result of latest read_some operation. const asio::error_code& error, // Number of bytes transferred so far. std::size_t bytes_transferred ); A return value of 0 indicates that the read operation is complete. A non-zero return value indicates the maximum number of bytes to be read on the next call to the stream's read_some function.

Returns

The number of bytes transferred.

Exceptions

asio::system_error

Thrown on failure.

read() [9/16]

template<typename SyncReadStream , typename Allocator , typename CompletionCondition >

std::size_t asio::read ( SyncReadStream &  s, basic_streambuf< Allocator > &  b, CompletionCondition  completion_condition, asio::error_code &  ec  )

inline

Attempt to read a certain amount of data from a stream before returning.

This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:

• The supplied buffer is full (that is, it has reached maximum size).

• The completion_condition function object returns 0.

This operation is implemented in terms of zero or more calls to the stream's read_some function.

Parameters

s	The stream from which the data is to be read. The type must support the SyncReadStream concept.
b	The basic_streambuf object into which the data will be read.
completion_condition	The function object to be called to determine whether the read operation is complete. The signature of the function object must be: std::size_t completion_condition( // Result of latest read_some operation. const asio::error_code& error, // Number of bytes transferred so far. std::size_t bytes_transferred ); A return value of 0 indicates that the read operation is complete. A non-zero return value indicates the maximum number of bytes to be read on the next call to the stream's read_some function.
ec	Set to indicate what error occurred, if any.

Returns

The number of bytes read. If an error occurs, returns the total number of bytes successfully transferred prior to the error.

read() [10/16]

template<typename SyncReadStream , typename Allocator >

std::size_t asio::read ( SyncReadStream &  s, basic_streambuf< Allocator > &  b  )

inline

Attempt to read a certain amount of data from a stream before returning.

This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:

• The supplied buffer is full (that is, it has reached maximum size).

• An error occurred.

This operation is implemented in terms of zero or more calls to the stream's read_some function.

Parameters

s	The stream from which the data is to be read. The type must support the SyncReadStream concept.
b	The basic_streambuf object into which the data will be read.

Returns

The number of bytes transferred.

Exceptions

asio::system_error

Thrown on failure.

Note

This overload is equivalent to calling:

asio::read(
   s, b,
   asio::transfer_all()); 

read() [11/16]

template<typename SyncReadStream , typename Allocator >

std::size_t asio::read ( SyncReadStream &  s, basic_streambuf< Allocator > &  b, asio::error_code &  ec  )

inline

Attempt to read a certain amount of data from a stream before returning.

This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:

• The supplied buffer is full (that is, it has reached maximum size).

• An error occurred.

This operation is implemented in terms of zero or more calls to the stream's read_some function.

Parameters

s	The stream from which the data is to be read. The type must support the SyncReadStream concept.
b	The basic_streambuf object into which the data will be read.
ec	Set to indicate what error occurred, if any.

Returns

The number of bytes transferred.

Note

This overload is equivalent to calling:

asio::read(
   s, b,
   asio::transfer_all(), ec); 

read() [12/16]

template<typename SyncReadStream , typename Allocator , typename CompletionCondition >

std::size_t asio::read ( SyncReadStream &  s, basic_streambuf< Allocator > &  b, CompletionCondition  completion_condition  )

inline

Attempt to read a certain amount of data from a stream before returning.

This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:

• The supplied buffer is full (that is, it has reached maximum size).

• The completion_condition function object returns 0.

This operation is implemented in terms of zero or more calls to the stream's read_some function.

Parameters

s	The stream from which the data is to be read. The type must support the SyncReadStream concept.
b	The basic_streambuf object into which the data will be read.
completion_condition	The function object to be called to determine whether the read operation is complete. The signature of the function object must be: std::size_t completion_condition( // Result of latest read_some operation. const asio::error_code& error, // Number of bytes transferred so far. std::size_t bytes_transferred ); A return value of 0 indicates that the read operation is complete. A non-zero return value indicates the maximum number of bytes to be read on the next call to the stream's read_some function.

Returns

The number of bytes transferred.

Exceptions

asio::system_error

Thrown on failure.

read() [13/16]

template<typename SyncReadStream , typename DynamicBuffer_v2 , typename CompletionCondition >

std::size_t asio::read	(	SyncReadStream &	s,
		DynamicBuffer_v2	buffers,
		CompletionCondition	completion_condition,
		asio::error_code &	ec,
		typename enable_if< is_dynamic_buffer_v2< DynamicBuffer_v2 >::value >::type *	= 0
	)

Attempt to read a certain amount of data from a stream before returning.

This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:

• The specified dynamic buffer sequence is full (that is, it has reached maximum size).

• The completion_condition function object returns 0.

This operation is implemented in terms of zero or more calls to the stream's read_some function.

Parameters

s	The stream from which the data is to be read. The type must support the SyncReadStream concept.
buffers	The dynamic buffer sequence into which the data will be read.
completion_condition	The function object to be called to determine whether the read operation is complete. The signature of the function object must be: std::size_t completion_condition( // Result of latest read_some operation. const asio::error_code& error, // Number of bytes transferred so far. std::size_t bytes_transferred ); A return value of 0 indicates that the read operation is complete. A non-zero return value indicates the maximum number of bytes to be read on the next call to the stream's read_some function.
ec	Set to indicate what error occurred, if any.

Returns

The number of bytes read. If an error occurs, returns the total number of bytes successfully transferred prior to the error.

read() [14/16]

template<typename SyncReadStream , typename DynamicBuffer_v2 >

std::size_t asio::read ( SyncReadStream &  s, DynamicBuffer_v2  buffers, typename enable_if< is_dynamic_buffer_v2< DynamicBuffer_v2 >::value >::type *  = 0  )

inline

Attempt to read a certain amount of data from a stream before returning.

This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:

• The specified dynamic buffer sequence is full (that is, it has reached maximum size).

• An error occurred.

This operation is implemented in terms of zero or more calls to the stream's read_some function.

Parameters

s	The stream from which the data is to be read. The type must support the SyncReadStream concept.
buffers	The dynamic buffer sequence into which the data will be read.

Returns

The number of bytes transferred.

Exceptions

asio::system_error

Thrown on failure.

Note

This overload is equivalent to calling:

asio::read(
   s, buffers,
   asio::transfer_all()); 

read() [15/16]

template<typename SyncReadStream , typename DynamicBuffer_v2 >

std::size_t asio::read ( SyncReadStream &  s, DynamicBuffer_v2  buffers, asio::error_code &  ec, typename enable_if< is_dynamic_buffer_v2< DynamicBuffer_v2 >::value >::type *  = 0  )

inline

Attempt to read a certain amount of data from a stream before returning.

This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:

• The supplied buffer is full (that is, it has reached maximum size).

• An error occurred.

This operation is implemented in terms of zero or more calls to the stream's read_some function.

Parameters

s	The stream from which the data is to be read. The type must support the SyncReadStream concept.
buffers	The dynamic buffer sequence into which the data will be read.
ec	Set to indicate what error occurred, if any.

Returns

The number of bytes transferred.

Note

This overload is equivalent to calling:

asio::read(
   s, buffers,
   asio::transfer_all(), ec); 

read() [16/16]

template<typename SyncReadStream , typename DynamicBuffer_v2 , typename CompletionCondition >

std::size_t asio::read ( SyncReadStream &  s, DynamicBuffer_v2  buffers, CompletionCondition  completion_condition, typename enable_if< is_dynamic_buffer_v2< DynamicBuffer_v2 >::value >::type *  = 0  )

inline

Attempt to read a certain amount of data from a stream before returning.

This function is used to read a certain number of bytes of data from a stream. The call will block until one of the following conditions is true:

• The specified dynamic buffer sequence is full (that is, it has reached maximum size).

• The completion_condition function object returns 0.

This operation is implemented in terms of zero or more calls to the stream's read_some function.

Parameters

s	The stream from which the data is to be read. The type must support the SyncReadStream concept.
buffers	The dynamic buffer sequence into which the data will be read.
completion_condition	The function object to be called to determine whether the read operation is complete. The signature of the function object must be: std::size_t completion_condition( // Result of latest read_some operation. const asio::error_code& error, // Number of bytes transferred so far. std::size_t bytes_transferred ); A return value of 0 indicates that the read operation is complete. A non-zero return value indicates the maximum number of bytes to be read on the next call to the stream's read_some function.

Returns

The number of bytes transferred.

Exceptions

asio::system_error

Thrown on failure.