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RedHat 9 (Linux i386) - man page for libcurl (redhat section 3)

libcurl(3)				 libcurl overview			       libcurl(3)

NAME
       libcurl - client-side URL transfers

DESCRIPTION
       This is an overview on how to use libcurl in your C programs. There are specific man pages
       for each function mentioned in here. There's also the  libcurl-the-guide  document  for	a
       complete tutorial to programming with libcurl.

       There  are  a  dozen custom bindings that bring libcurl access to your favourite language.
       Look elsewhere for documentation on those.

       All applications that use libcurl should call curl_global_init() exactly once  before  any
       libcurl	function  can  be  used.  After  all  usage  of libcurl is complete, it must call
       curl_global_cleanup(). In between those two calls, you can use libcurl as described below.

       When using libcurl's "easy" interface you init your session and get a  handle,  which  you
       use as input to the easy interface functions you use. Use curl_easy_init() to get the han-
       dle. There is also the so called "multi" interface, try the libcurl-multi(3) man page  for
       an overview of that.

       You  continue by setting all the options you want in the upcoming transfer, most important
       among them is the URL itself (you can't transfer anything without a specified URL  as  you
       may  have figured out yourself). You might want to set some callbacks as well that will be
       called from the library when data is available etc.  curl_easy_setopt() is there for this.

       When all is setup, you tell libcurl to perform the transfer using curl_easy_perform().  It
       will then do the entire operation and won't return until it is done (successfully or not).

       After the transfer has been made, you can set new options and make another transfer, or if
       you're done, cleanup the session by calling curl_easy_cleanup().  If you  want  persistant
       connections, you don't cleanup immediately, but instead run ahead and perform other trans-
       fers using the same handle. See the chapter below for Persistant Connections.

       There is also a series of other helpful functions to use. They are:

	      curl_version()
			displays the libcurl version

	      curl_getdate()
			converts a date string to time_t

	      curl_getenv()
			portable environment variable reader

	      curl_easy_getinfo()
			get information about a performed transfer

	      curl_formadd()
			helps building a HTTP form POST

	      curl_formfree()
			free a list built with curl_formparse()/curl_formadd()

	      curl_slist_append()
			builds a linked list

	      curl_slist_free_all()
			frees a whole curl_slist

	      curl_mprintf()
			portable printf() functions

	      curl_strequal()
			portable case insensitive string comparisons

LINKING WITH LIBCURL
       On unix-like machines, there's a tool named curl-config that gets installed with the  rest
       of the curl stuff when 'make install' is performed.

       curl-config  is added to make it easier for applications to link with libcurl and develop-
       ers to learn about libcurl and how to use it.

       Run 'curl-config --libs' to get the (additional) linker options you need to link with  the
       particular version of libcurl you've installed.

       For details, see the curl-config.1 man page.

LIBCURL SYMBOL NAMES
       All  public functions in the libcurl interface are prefixed with 'curl_' (with a lowercase
       c). You can find other functions in the library source code, but other  prefixes  indicate
       the functions are private and may change without further notice in the next release.

       Only use documented functions and functionality!

PORTABILITY
       libcurl works exactly the same, on any of the platforms it compiles and builds on.

THREADS
       Never  ever call curl-functions simultaneously using the same handle from several threads.
       libcurl is thread-safe and can be used in any number of threads, but you must use separate
       curl handles if you want to use libcurl in more than one thread simultaneously.

PERSISTANT CONNECTIONS
       Persistent  connections	means  that  libcurl  can  re-use the same connection for several
       transfers, if the conditions are right.

       libcurl	will  *always*	attempt  to  use  persistent  connections.   Whenever	you   use
       curl_easy_perform(),  libcurl  will attempt to use an existing connection to do the trans-
       fer, and if none exists it'll open a new one that will be subject for re-use on a possible
       following call to curl_easy_perform().

       To  allow  libcurl to take full advantage of persistent connections, you should do as many
       of  your  file  transfers  as  possible	using  the  same  curl	handle.  When  you   call
       curl_easy_cleanup(),  all the possibly open connections held by libcurl will be closed and
       forgotten.

       Note that the options set  with	curl_easy_setopt()  will  be  used  in	on  every  repeat
       curl_easy_perform() call

libcurl 7.9.6				  19 March 2002 			       libcurl(3)


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