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Re: Downloading web pages using threads

From: Sam Couter <sam@topic.com.au>
Date: Wed, 5 Apr 2000 09:16:57 +1000
To: Phil Inglis <inglisphil@home.com>
Cc: www-lib@w3.org
Message-ID: <20000405091657.C26828@mail.topic.com.au>
Phil Inglis <inglisphil@home.com> wrote:
> Hello, I am using libwww to download web pages. I have about 25 I want to download at around the same time. Right now I download one, when it finishes I start the other. I have add threading to speed this up but it seems that only the first thread goes through and all the others get terminated. It seems to me this is because they are all using the same memory space. If it were written using classes I don't see this would be a problem. Is there any special commands I have to give to download using threads? Below is the code I used in each thread.
[ code snipped ]

libwww is *NOT* threadsafe. Don't try to use it from more than one thread.
I think you're lucky that even the first one was completed. :)

One solution you can use is:

HTNet_addAfter(terminate_handler, NULL, NULL, HT_ALL, HT_FILTER_LAST);
while (there_are_more_files_to_get) {
	request = HTRequest_new();
	status = HTLoadToFile(url, request, outputfile);

This will go and get all the files you asked for, using what libwww calls
"psuedothreads". It will also use funky features like pipelining and
multiple simultaneous sockets (one for each host) to increase performance.
Sam Couter                                              sam@topic.com.au
Internet Engineer                               http://www.topic.com.au/
tSA Consulting

Received on Tuesday, 4 April 2000 19:17:18 UTC

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