GET (TCP/IP statement): Difference between revisions

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(Created page with "'''GET''' reads unformatted (raw) data from an open TCP/IP connection opened with _OPENCLIENT, _OPENHOST or _OPENCONNECTION. {{PageSyntax}} ''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''...")
 
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{{CodeStart}}
{{CodeStart}}
  {{Cl|PUT|PUT #}}​c, , a$ ' sends data  
  {{Cl|PUT|PUT #}}​c, , a$ ' sends data
  {{Cl|GET|GET #}}​o, , b$ ' reads any available data into variable length string b$
  {{Cl|GET|GET #}}​o, , b$ ' reads any available data into variable length string b$
  {{Cl|GET|GET #}}​o, , x% ' if 2 bytes are available, they are read into x%
  {{Cl|GET|GET #}}​o, , x% ' if 2 bytes are available, they are read into x%
{{CodeEnd}}
{{CodeEnd}}


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





Revision as of 01:43, 23 January 2023

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.


Examples

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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