more accurate

                                       Updated for curl 7.8 on May 29, 2001

                                    Updated for curl 7.9.1 on November 2, 2001

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 makes sure we stay absolutely platform independent.

 curl_easy_init() allocates an internal struct and makes some initializations.

 The returned handle does not reveal internals. This is the 'UrlData' struct

 which works as a global "anchor" struct. All connections performed will get

 connect-specific data allocated that should be used for things related to

 particular connections/requests.

 The returned handle does not reveal internals. This is the 'SessionHandle'

 struct which works as an "anchor" struct for all curl_easy functions. All

 connections performed will get connect-specific data allocated that should be

 used for things related to particular connections/requests.

 curl_easy_setopt() takes three arguments, where the option stuff must be

 passed in pairs: the parameter-ID and the parameter-value. The list of

 options is documented in the man page. This function mainly sets things in

 the 'UrlData' struct.

 the 'SessionHandle' struct.

 curl_easy_perform() does a whole lot of things:

   This function makes sure there's an allocated and initiated 'connectdata'

   struct that is used for this particular connection only (although there may

   be several requests performed on the same connect). A bunch of things are

   inited/inherited from the UrlData struct.

   inited/inherited from the SessionHandle struct.

 o Curl_do()

   Curl_Transfer() function (in lib/transfer.c) to setup the transfer and

   returns.

   Starting in 7.9.1, if this DO function fails and the connection is being

   re-used, libcurl will then close this connection, setup a new connection

   and re-issue the DO request on that. This is because there is no way to be

   perfectly sure that we have discovered a dead connection before the DO

   function and thus we might wrongly be re-using a connection that was closed

   by the remote peer.

 o Transfer()

   Curl_perform() then calls Transfer() in lib/transfer.c that performs

 o Curl_disconnect()

   When doing normal connections and transfers, no one ever tries to close any

   connection so this is not normally called when curl_easy_perform() is

   connections so this is not normally called when curl_easy_perform() is

   used. This function is only used when we are certain that no more transfers

   is going to be made on the connection. It can be also closed by force, or

   it can be called to make sure that libcurl doesn't keep too many

 The persistent connection support in libcurl requires some considerations on

 how to do things inside of the library.

 o The 'UrlData' struct returned in the curl_easy_init() call must never

   hold connection-oriented data. It is meant to hold the root data as well

   as all the options etc that the library-user may choose.

 o The 'UrlData' struct holds the "connection cache" (an array of pointers to

   'connectdata' structs). There's one connectdata struct allocated for each

   connection that libcurl knows about.

 o The 'SessionHandle' struct returned in the curl_easy_init() call must never

   hold connection-oriented data. It is meant to hold the root data as well as

   all the options etc that the library-user may choose.

 o The 'SessionHandle' struct holds the "connection cache" (an array of

   pointers to 'connectdata' structs). There's one connectdata struct

   allocated for each connection that libcurl knows about.

 o This also enables the 'curl handle' to be reused on subsequent transfers,

   something that was illegal before libcurl 7.7.

 o When we are about to perform a transfer with curl_easy_perform(), we first