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Re: limits of independent curl connections

From: Tom K. <>
Date: Mon, 25 Feb 2013 22:16:28 -0600

I've an update, hopefully this can get us closer to a resolution.

>> When everything "locks up" as you say, does the machine really stop working
>> or is there network traffic still going on?

Traffic does cease, it is unresponsive to RDP/remote debugging. I
can't even force the OS to bluescreen via the key combo to get a
kernel dump. The only response I've found it will give is ping.

>> To me, this sounds like a serious problem somewhere to a level that libcurl
>> shouldn't even be capable of doing. Like a network driver problem or so.

I would agree that I don't think this should be able to happen in user
mode, but it seems to be happening. I've tried it with the
AV/firewall off, on different sets of hardware all with the same

This example creates a CURL handle and then sends data in a loop. I
start 200 of these applications up and eventually the system will
become unresponsive to the point of having to press the power button.

Here is the main file. Maybe I'm doing something wrong.

Here is the bat file I run which reproduces the error on the systems
which I tested on. You'll end up with one cmd window and a bunch of
noise. You can close the window to kill them all.

I included the libcurl binary which I use. Its built with winssl,
though I rebuilt it without winssl to the same effect and haven't been
using https urls for my testing.

I included the solution files. I generate them with cmake so they
would usually not be checked into source, hopefully I didn't miss
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Received on 2013-02-26