asio::read

Attempt to read 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)
	Attempt to read a certain amount of data from a stream before returning.
template<typename SyncReadStream , typename MutableBufferSequence , typename CompletionCondition >
std::size_t	asio::read (SyncReadStream &s, const MutableBufferSequence &buffers, CompletionCondition completion_condition)
	Attempt to read a certain amount of data from a stream before returning.
template<typename SyncReadStream , typename MutableBufferSequence , typename CompletionCondition >
std::size_t	asio::read (SyncReadStream &s, const MutableBufferSequence &buffers, CompletionCondition completion_condition, asio::error_code &ec)
	Attempt to read a certain amount of data from a stream before returning.
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.
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.
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.

---

Detailed Description

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

---

Function Documentation

template<typename SyncReadStream , typename MutableBufferSequence >

std::size_t asio::read	(	SyncReadStream &	s,
		const MutableBufferSequence &	buffers
	)

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 one 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()); 

template<typename SyncReadStream , typename MutableBufferSequence , typename CompletionCondition >

std::size_t asio::read	(	SyncReadStream &	s,
		const MutableBufferSequence &	buffers,
		CompletionCondition	completion_condition
	)

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 true.

This operation is implemented in terms of one 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: bool completion_condition( const asio::error_code& error, // Result of latest read_some // operation. std::size_t bytes_transferred // Number of bytes transferred // so far. ); A return value of true indicates that the read operation is complete. False indicates that further calls to the stream's read_some function are required.

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.

template<typename SyncReadStream , typename MutableBufferSequence , typename CompletionCondition >

std::size_t asio::read	(	SyncReadStream &	s,
		const MutableBufferSequence &	buffers,
		CompletionCondition	completion_condition,
		asio::error_code &	ec
	)

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 true.

This operation is implemented in terms of one 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: bool completion_condition( const asio::error_code& error, // Result of latest read_some // operation. std::size_t bytes_transferred // Number of bytes transferred // so far. ); A return value of true indicates that the read operation is complete. False indicates that further calls to the stream's read_some function are required.
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.

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.

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:

• An error occurred.

This operation is implemented in terms of one 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()); 

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.

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 completion_condition function object returns true.

This operation is implemented in terms of one 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: bool completion_condition( const asio::error_code& error, // Result of latest read_some // operation. std::size_t bytes_transferred // Number of bytes transferred // so far. ); A return value of true indicates that the read operation is complete. False indicates that further calls to the stream's read_some function are required.

Returns:

The number of bytes transferred.

Exceptions:

asio::system_error

Thrown on failure.

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.

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 completion_condition function object returns true.

This operation is implemented in terms of one 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: bool completion_condition( const asio::error_code& error, // Result of latest read_some // operation. std::size_t bytes_transferred // Number of bytes transferred // so far. ); A return value of true indicates that the read operation is complete. False indicates that further calls to the stream's read_some function are required.
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.