GET (TCP/IP statement)

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GET reads unformatted (raw) data from an open TCP/IP connection opened with _OPENCLIENT, _OPENHOST or _OPENCONNECTION.


Syntax

Syntax 1 (using variable strings)
GET #handle&, , dat$
  • Using the handle& return value from _OPENCLIENT, _OPENHOST or _OPENCONNECTION, the function reads any available data into variable length string dat$, the string length is adjusted to the number of bytes read, so checking EOF is unnecessary.
Syntax 2 (using fixed length variables/strings)
GET #handle&, , dat%
  • Using the handle& return value from _OPENCLIENT, _OPENHOST or _OPENCONNECTION, the function reads an INTEGER (in the shown syntax, due to the use of an integer (%) variable). If 2 bytes for the integer are available, they are read into dat%, if not then nothing is read and EOF handle& will return -1 (dat% its value will be undefined in the latter case).


Communicating using unformatted/raw streamed data

  • Benefit: Communicate with any TCP/IP compatible protocol (eg. FTP, HTTP, web-pages, etc).
  • Disadvantage: Streamed data has no 'message length', as such just the program deals with a continuous number of bytes in a row. Some messages get fragmented and parts of messages can (and often do) arrive at different times, due to the very nature of the TCP/IP protocol.
  • The position parameter (between the commas) is not used in TCP/IP connections.
  • The programmer must cater for these situations manually.


Examples

Example
Reading data of various lengths
GET #handle&, , dat$ 'always reads any available data into variable length string
GET #handle&, , dat% 'if 2 bytes (INTEGER) are available, they are read, else nothing is read
GET #handle&, , dat& 'if 4 bytes (LONG) are available, they are read, else nothing is read
GET #handle&, , dat&& 'if 8 bytes (_INTEGER64) are available, they are read, else nothing is read

More examples


See also



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