updated to be more valid for version 7 workings

 the Windows way. The four most notable details are:

 1. Different function names for close(), read(), write()

 2. Windows requires a couple of init calls

 2. Windows requires a couple of init calls for the socket stuff

 3. The file descriptors for network communication and file operations are

    not easily interchangable as in unix

 4. When writing data to stdout, Windows makes end-of-lines the DOS way, thus

    destroying binary data, although you do want that conversion if it is

    text coming through... (sigh)

 In curl, (1) and (2) are done with defines and macros, so that the source

 looks the same at all places except for the header file that defines them.

 In curl, (1) is made with defines and macros, so that the source looks the

 same at all places except for the header file that defines them.

 (2) must be made by the application that uses libcurl, in curl that means

 src/main.c has some code #ifdef'ed to do just that.

 (3) is simply avoided by not trying any funny tricks on file descriptors.

Library

=======

 There is a few entry points to the library, namely each publicly defined

 As described elsewhere, libcurl is meant to get two different "layers" of

 interface. At the present point only the high-level, the "easy", interface

 has been fully implemented and thus documented. We assume the easy-interface

 in this description, the low-level interface will be documented when fully

 implemented.

 There are plenty of entry points to the library, namely each publicly defined

 function that libcurl offers to applications. All of those functions are

 rather small and easy-to-follow, accept the one single and do-it-all named

 curl_urlget() (entry point in lib/url.c).

 rather small and easy-to-follow. All the ones prefixed with 'curl_easy' are

 put in the lib/easy.c file.

 curl_urlget() takes a variable amount of arguments, and they must all be

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

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

 arguments must be ended with a end-of-arguments parameter-ID.

 options is documented in the man page.

 The function then continues to analyze the URL, get the different components

 and connects to the remote host. This may involve using a proxy and/or using

 SSL. The GetHost() function in lib/hostip.c is used for looking up host

 names.

 curl_easy_perform() does a whole lot of things.

 The function analyzes the URL, get the different components and connects to

 the remote host. This may involve using a proxy and/or using SSL. The

 GetHost() function in lib/hostip.c is used for looking up host names.

 When connected, the proper function is called. The functions are named after

 the protocols they handle. ftp(), http(), dict(), etc. They all reside in

 supplied clones in lib/mprintf.c.

 While transfering, the progress functions in lib/progress.c are called at a

 frequent interval. The speedcheck functions in lib/speedcheck.c are also used

 to verify that the transfer is as fast as required.

 frequent interval (or at the user's choice, a specified callback might get

 called). The speedcheck functions in lib/speedcheck.c are also used to verify

 that the transfer is as fast as required.

 When the operation is done, the writeout() function in lib/writeout.c may be

 called to report about the operation as specified previously in the arguments

 to curl_urlget().

 to curl_easy_setopt().

 When completed curl_easy_cleanup() should be called to free up used

 resources.

 HTTP(S)

 (lib/cookie.c).

 HTTPS uses in almost every means the same procedure as HTTP, with only two

 exceptions: the connect procedure is different and the function used

 exceptions: the connect procedure is different and the function used to read

 or write from the socket is different, although the latter fact is hidden in

 the source by the use of curl_read() for reading and curl_write() for writing

 data to the remote server.

 FTP

 The if2ip() function can be used for getting the IP number of a specified

 network interface, and it resides in lib/if2ip.c

 network interface, and it resides in lib/if2ip.c. It is only used for the FTP

 PORT command.

 TELNET

 is found in lib/escape.c.

 While transfering data in Transfer() a few functions might get

 used. get_date() in lib/getdate.c is for HTTP date comparisons.

 used. curl_getdate() in lib/getdate.c is for HTTP date comparisons (and

 more).

 lib/getenv.c is for reading environment variables in a neat platform

 independent way. That's used in the client, but also in lib/url.c when

 checking the PROXY variables.

 lib/getenv.c offers curl_getenv() which is for reading environment variables

 in a neat platform independent way. That's used in the client, but also in

 lib/url.c when checking the PROXY variables.

 lib/netrc.c keeps the .netrc parser

 functions used for the multiple-URL support.

 The client mostly mess around to setup its config struct properly, then it

 calls the curl_urlget() function in the library and when it gets back control

 it checks status and exits.

 calls the curl_easy_*() functions of the library and when it gets back

 control after the curl_easy_perform() it cleans up the library, checks status

 and exits.