FAQ


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Date: 15 March 2000

             Frequently Asked Questions about Curl

1. Problems connecting to SSL servers.

  It took a very long time before I could sort out why curl had problems
  to connect to certain SSL servers when using SSLeay or OpenSSL v0.9+.
  The error sometimes showed up similar to:

  16570:error:1407D071:SSL routines:SSL2_READ:bad mac decode:s2_pkt.c:233:

  It turned out to be because many older SSL servers don't deal with SSLv3
  requests properly. To correct this problem, tell curl to select SSLv2 from
  the command line (-2/--sslv2).

  I have also seen examples where the remote server didn't like the SSLv2
  request and instead you had to force curl to use SSLv3 with -3/--sslv3.

2. Does curl support resume?

  Yes. Both ways on FTP, download ways on HTTP.

3. Is libcurl thread safe?

  Yes, as far as curl's own code goes. It does use system calls that often
  aren't thread safe in most environments, such as gethostbyname().

  I am very interested in once and for all getting some kind of report or
  README file from those who have used libcurl in a threaded environment,
  since I haven't and I get this question more and more frequently!

4. Why doesn't my posting using -F work?

  You can't simply use -F or -d at your choice. The web server that will
  receive your post assumes one of the formats. If the form you're trying to
  "fake" sets the type to 'multipart/form-data', than and only then you must
  use the -F type. In all the most common cases, you should use -d which then
  causes a posting with the type 'application/x-www-form-urlencoded'.