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Read up to a line of data from the server and returns it in a
string buffer.
Syntax
object.ReadLine( Buffer, [Length] )
Parameters
- Buffer
- A string that the data will be stored in when the method
returns. This parameter must be passed by reference.
- Length
- An optional parameter that specifies the maximum number of bytes
to read. If this argument is omitted, then the control will return
up to 4096 characters in the string. If the application expects that
a single line of text will exceed this value, then it must be
explicitly specified.
Return Value
This method will return true if a line of data has been read. If
an error occurs or there is no more data available to read, then the
method will return False. It is possible for data to be returned in
the string buffer even if the return value is false. Applications
should check the length of the string after the method returns to
determine if any data was copied into the buffer. For example, if a
timeout occurs while the method is waiting for more data to arrive on
the socket, it will return zero; however, data may have already been
copied into the string buffer prior to the error condition. It is the
responsibility of the application to process that data, regardless of
the function return value.
Remarks
The ReadLine method reads data from the server up to the
specified number of bytes or until an end-of-line character sequence
is encountered. Unlike the Read method which reads arbitrary
bytes of data, this function is specifically designed to return a
single line of text data in a string variable. When an end-of-line
character sequence is encountered, the function will stop and return
the data up to that point; the string will not contain the
carriage-return or linefeed characters.
There are some limitations when using the ReadLine method.
The method should only be used to read text, never binary data. In
particular, it will discard nulls, linefeed and carriage return
control characters. This method will force the thread to block until
an end-of-line character sequence is processed, the read operation
times out or the server closes its end of the socket connection.
If the Blocking property is set to False, calling this method
will automatically switch the socket into a blocking mode, read the
data and then restore the socket to non-blocking mode. If another
network operation is attempted while ReadLine is blocked
waiting for data from the server, an error will occur. It is
recommended that this method only be used with blocking
connections.
The Read and ReadLine methods can be intermixed,
however be aware that the Read method will consume any data
that has already been buffered by the ReadLine method and this
may have unexpected results.
See Also
CodePage Property,
IsReadable Property,
Timeout Property,
Read Method,
Write Method,
WriteLine Method
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