separated the easy-specific stuff into a new libcurl-easy.3 man page and

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.TH libcurl 3 "12 Aug 2003" "libcurl 7.10.7" "libcurl easy interface"

.SH NAME

libcurl-easy \- easy interface overview

.SH DESCRIPTION

When using libcurl's "easy" interface you init your session and get a handle

(often referred to as an "easy handle" in various docs and sources), which you

use as input to the easy interface functions you use. Use

\fIcurl_easy_init()\fP to get the handle.

You continue by setting all the options you want in the upcoming transfer, the

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. \fIcurl_easy_setopt()\fP is used for all this.

When all is setup, you tell libcurl to perform the transfer using

\fIcurl_easy_perform()\fP.  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

\fIcurl_easy_cleanup()\fP. If you want persistant connections, you don't

cleanup immediately, but instead run ahead and perform other transfers using

the same easy handle.

libcurl \- client-side URL transfers

.SH 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.

specific man pages for each function mentioned in here. There are also the

\fIlibcurl-easy\fP man page, the \fIlibcurl-multi\fP man page, the

\fIlibcurl-share\fP man page and the \fIlibcurl-the-guide\fP document for

further reading on how to do programming with libcurl.

There are a dozen custom bindings that bring libcurl access to your favourite

language. Look elsewhere for documentation on those.

There exist more than 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 \fIcurl_global_init()\fP exactly

once before any libcurl function can be used. After all usage of libcurl is

complete, it \fBmust\fP call \fIcurl_global_cleanup()\fP. 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

\fIcurl_easy_init()\fP to get the handle. There is also the so called "multi"

interface, try the \fIlibcurl-multi(3)\fP man page for an overview of that.

To transfer files, you always set up an "easy handle" using

\fIcurl_easy_init()\fP, but when you want the file(s) transfered you have the

option of using the "easy" interface, or the "multi" interface.

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.  \fIcurl_easy_setopt()\fP is there for this.

The easy interface is a synchronous interface with which you call

\fIcurl_easy_perform\fP and let it perform the transfer. When it is completed,

the function return and you can continue. More details are found in the

\fIlibcurl-easy\fP man page.

When all is setup, you tell libcurl to perform the transfer using

\fIcurl_easy_perform()\fP.  It will then do the entire operation and won't

return until it is done (successfully or not).

The multi interface on the other hand is an asynchronous interface, that you

call and that performs only a little piece of the tranfer on each invoke. It

is perfect if you want to do things while the transfer is in progress, or

similar. The multi interface allows you to select() on libcurl action, and

even to easily download multiple files simultaneously using a single thread.

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

\fIcurl_easy_cleanup()\fP.  If you want persistant connections, you don't

cleanup immediately, but instead run ahead and perform other transfers using

the same handle. See the chapter below for Persistant Connections.

You can have multiple easy handles share certain data, even if they are used

in different threads. This magic is setup using the share interface, as

described in the \fIlibcurl-share\fP man page.

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

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 transfer, 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().

\fIcurl_easy_perform()\fP or \fIcurl_multi_perform()\fP, libcurl will attempt

to use an existing connection to do the transfer, and if none exists it'll

open a new one that will be subject for re-use on a possible following call to

\fIcurl_easy_perform()\fP or \fIcurl_multi_perform()\fP.

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

you call \fIcurl_easy_cleanup()\fP, 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

Note that the options set with \fIcurl_easy_setopt()\fP will be used in on

every repeated \fIcurl_easy_perform()\fP call.