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GET (TCP IP statement)

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Samuel Gomes edited this page Nov 8, 2022 · 1 revision

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

Syntax

Syntax 1:

GET #handle, , b$

  • Reads any available data into variable length string b$ (b$'s length is adjusted to the number of bytes read, so checking EOF is unnecessary) using the handle return value from _OPENCLIENT, _OPENHOST or _OPENCONNECTION.

Syntax 2:

GET #handle, ,x%

  • Reads an integer. If 2 bytes are available, they are read into x%, if not then nothing is read and EOF(handle) will return -1 (and x%'s value will be undefined) using the handle return value from _OPENCLIENT, _OPENHOST or _OPENCONNECTION.

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.

Example(s)

Example:

 PUT #​c, , a$ ' sends data 
 GET #​o, , b$ ' reads any available data into variable length string b$  
 GET #​o, , x% ' if 2 bytes are available, they are read into x%

Explanation:

  • Data could be a string, variable array, user defined TYPE, etc.
  • b$'s length is adjusted to the number of bytes read. Checking EOF(o) is unnecessary.
  • If 2 bytes are not available for the x% integer then nothing is read and EOF(o) will return -1

More Examples

See Also

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