LNET CanSend is not always triggerd [Source attached now]
lazarus / 38-Networking and Web Programming

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MaartenJB · 2019-12-30 11:39

Hi,

I've go a simple lnet client server, the client sends data to the
server, but once out of about 10 times the "CanSend" is not being
triggered on the client side. When I do a manual trigger like this:
"TcpClientCanSend( TcpClient.Iterator )" the sending continues
successfully.

Does anyone have a clue what this can be?

Best regards,

Maarten

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MaartenJB · 2019-12-31 11:29

I've attached the source of a very basic application that shows the
problem. It automatically connects and disconnects and detects if a
CanSend has been fired or not. Sometimes it fails right away,
sometimes it takes a while. When it fails there is a button "Force
CanSend" and when pressed it continues.

I've also attached two pictures, one of how it should look and one
where the CanSend is not fired.

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MarkMLl · 2019-12-31 11:55

What OS is this with? I did some maintenance on that years ago (adding
Telnet subcommands IIRC) but from discussion at the time I'm not sure
the support state... I think lnet was intended more as something used
during installation etc. than for heavyweight development.

MarkMLl

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MaartenJB · 2019-12-31 12:44

Hi Mark,

This is on Windows 10 (1809). I've tested it on multiple computers.

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MarkMLl · 2019-12-31 13:24

I suspect you've just become the local expert :-)

MarkMLl

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MaartenJB · 2020-01-02 07:44

Aaah, that's not a good thing :-)

What component is recommend to use for IP communication in free
pascal?

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MarkMLl · 2020-01-02 09:18

Sorry, can't answer that one since my use cases tend to be "unusual"
which usually results in my going direct to low-level functions.

I've used lnet for a Telnet terminal emulator (to the Hercules
mainframe emulator etc.) and in that role it appeared reliable, but
the code isn't in day-to-day use so if something only went wrong every
thousand messages or so I might not have noticed.

Hopefully somebody else has an opinion, but if not I suggest starting
a new thread with a concise description of what you're trying to do in
the subject line.

MarkMLl