[fpc-pascal] socket timeout

[Fabio Luis Girardi]

For connect, I wrote a unit that implements a connect timeout, see:

http://sourceforge.net/p/pascalscada/code/HEAD/tree/trunk/src/scada/sockets_w32_w64.pas#l70

or

http://sourceforge.net/p/pascalscada/code/HEAD/tree/trunk/src/scada/sockets_unix.pas#l48

If you want work in blocking mode after connect, do something like this:


fsocket = {$IFDEF WINDOWS}Socket{$ELSE}fpSocket{$ENDIF}(PF_INET,
SOCK_STREAM, IPPROTO_TCP)

//set socket options.

setblockingmode(fsocket,MODE_NONBLOCKING);

if connect_with_timeout(focket, at channel,sizeof(channel),FTimeoutInMs)<>0
then begin
  //check errors
end;

setblockingmode(FSocket,MODE_BLOCKING);

2013/4/17 Rainer Stratmann <rainerstratmann at t-online.de>:
>  On Wednesday 17 April 2013 10:22:58 you wrote:
>> I thought MSG_DONTWAIT is actually the flag to switch to nonblocking mode,
>> isn't it?
> May be.
>> As a matter of fact, the fprecv() above would get a result of -1
>> and a sockterror of "Try Again", which is exactly the behavior of
>> nonblocking read.
> Yes it seems so.
>
> I do always separately switch to the nonblocking mode before.
>>
>>
>> 2013/4/17 Rainer Stratmann <rainerstratmann at t-online.de>
>>
>> >  On Wednesday 17 April 2013 09:17:09 you wrote:
>> > > Will this be a CPU hog:
>> > >
>> > > t := Now;
>> > > while fprecv(s, @buf, buf_len, MSG_DONTWAIT) < 0 do begin
>> > >
>> > >   if Now - t > 0.00001 * timeout then Break;   // approx. <timeout>
>> >
>> > seconds
>> >
>> > > end;
>> > >
>> > > Thanks
>> >
>> > I did not read the whole thread, but that you favorite blocking mode
>> > (which I
>> > don't use).
>> >
>> > For MSG_DONTWAIT as far I know you have to change to the nonblocking
>> > mode.
>> >
>> > > 2013/4/16 Luca Olivetti <luca at ventoso.org>
>> > >
>> > > > Al 16/04/13 12:20, En/na Michael Schnell ha escrit:
>> > > > > On 04/16/2013 11:26 AM, Xiangrong Fang wrote:
>> > > > >> How can I set the connection and read/write timeout when using
>> >
>> > socket
>> >
>> > > > >> in free pascal?
>> > > > >
>> > > > > I seem to remember that synapse can do this.
>> > > >
>> > > > Only in svn and it does it this way
>> > > >
>> > > > if FConnectionTimeout > 0 then
>> > > > begin
>> > > >
>> > > >   // connect in non-blocking mode
>> > > >   b := NonBlockMode;
>> > > >   NonBlockMode := true;
>> > > >   SockCheck(synsock.Connect(FSocket, Sin));
>> > > >   if (FLastError = WSAEINPROGRESS) OR (FLastError = WSAEWOULDBLOCK)
>> >
>> > then
>> >
>> > > >     if not CanWrite(FConnectionTimeout) then
>> > > >
>> > > >       FLastError := WSAETIMEDOUT;
>> > > >
>> > > >   NonBlockMode := b;
>> > > >
>> > > > end
>> > > > else
>> > > >
>> > > >   SockCheck(synsock.Connect(FSocket, Sin));
>> > > >
>> > > > NonBlockMode in turn uses fpIoCtl with the FIONBIO parameter,
>> > > > WSAEINPROGRESS=EsysEINPROGRESS, WSAEWOULDBLOCK=EsysEWOULDBLOCK and
>> > > > CanWrite  does an fpSelect
>> > > >
>> > > > Bye
>> > > > --
>> > > > Luca
>> > > >
>> > > > _______________________________________________
>> > > > fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
>> > > > http://lists.freepascal.org/mailman/listinfo/fpc-pascal
>> >
>> > _______________________________________________
>> > fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
>> > http://lists.freepascal.org/mailman/listinfo/fpc-pascal
> _______________________________________________
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> http://lists.freepascal.org/mailman/listinfo/fpc-pascal



-- 
The best regards,

Fabio Luis Girardi
PascalSCADA Project
http://sourceforge.net/projects/pascalscada
http://www.pascalscada.com