QB64-PE/internal/help/_OPENCONNECTION.txt

{{DISPLAYTITLE:_OPENCONNECTION}}
The [[_OPENCONNECTION]] function opens a connection from a client that the host has detected and returns a status handle.


{{PageSyntax}}
:{{Parameter|connectHandle}} = [[_OPENCONNECTION]]({{Parameter|hostHandle}})


{{PageDescription}} 
* Valid {{Parameter|connectHandle}} values returned are negative numbers.
* If the syntax is correct but they fail to begin/connect, a {{Parameter|connectHandle}} of 0 is returned. 
* Always check if the handle returned is 0 (failed) before continuing.  
* [[CLOSE]] #{{Parameter|connectHandle}} closes the connection. Failed connections({{Parameter|connectHandle}} = 0) do not need to be closed.
* As a '''Host''' you can check for new clients (users). Each will have a unique connection handle.
* Creates an [[ERROR Codes|Illegal Function Call]] error if called with a string argument of the wrong syntax.
* Handle values can be used as the open number by [[INPUT (TCP/IP statement)|INPUT #]] or [[GET (TCP/IP statement)|GET #]] read statements and [[PUT (TCP/IP statement)|PUT #]] or [[PRINT (TCP/IP statement)|PRINT #]] write statements.


{{PageExamples}}
''Example:'' Using the [[_OPENCONNECTION]] new client return with [[INPUT (TCP/IP statement)|INPUT]] # or [[GET (TCP/IP statement)|GET]] # message or data reads.

{{CodeStart}}

 host = {{Cl|_OPENHOST}}("TCP/IP:8080")
 {{Cl|DO}}
   newclient = {{Cl|_OPENCONNECTION}}(host) ' monitor host connection
   {{Cl|IF...THEN|IF}} newclient {{Cl|THEN}}
     {{Cl|SLEEP}} 1 ' wait one second for data to arrive
     {{Cl|INPUT (TCP/IP statement)|INPUT}} #newclient, a
     {{Cl|PRINT}} a 
     {{Cl|CLOSE}} #newclient ' close after each read
   {{Cl|ELSE}} : {{Cl|_DELAY}} .05 ' share resources with other programs (20 loops per second)
   {{Cl|END IF}}
 {{Cl|LOOP}} {{Cl|UNTIL}} {{Cl|INKEY$}} <> "" ' any keypress quits
 {{Cl|CLOSE}} #host
 {{Cl|SYSTEM}}

{{CodeEnd}}

''Explanation:'' The function finds new clients and waits one second to read a message or other data. If a message or data was sent, it displays it on the screen and closes the connection. 

'''Note: When sending data, the client should wait about 3 seconds before closing their connection!'''


{{PageSeeAlso}}
* [[_OPENHOST]], [[_OPENCLIENT]]
* [[_CONNECTED]], [[_CONNECTIONADDRESS]]


{{PageNavigation}}