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

libcurl \- client-side URL transfers

.SH DESCRIPTION

.SH DESCRIPTION

This is an overview on how to use libcurl in your C programs. There are

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

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

libcurl-the-guide document for a complete tutorial to programming with

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

libcurl.

\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

There exist more than a dozen custom bindings that bring libcurl access to

language. Look elsewhere for documentation on those.

your favourite language. Look elsewhere for documentation on those.

All applications that use libcurl should call \fIcurl_global_init()\fP exactly

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

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

complete, it \fBmust\fP call \fIcurl_global_cleanup()\fP. In between those two

calls, you can use libcurl as described below.

calls, you can use libcurl as described below.

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

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

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

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

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

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

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

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

The easy interface is a synchronous interface with which you call

most important among them is the URL itself (you can't transfer anything

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

without a specified URL as you may have figured out yourself). You might want

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

to set some callbacks as well that will be called from the library when data

\fIlibcurl-easy\fP man page.

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

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

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

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

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

return until it is done (successfully or not).

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

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

transfer, or if you're done, cleanup the session by calling

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

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

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

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

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

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

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

several transfers, if the conditions are right.

several transfers, if the conditions are right.

libcurl will *always* attempt to use persistent connections. Whenever you use

libcurl will *always* attempt to use persistent connections. Whenever you use

curl_easy_perform(), libcurl will attempt to use an existing connection to do

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

the transfer, and if none exists it'll open a new one that will be subject for

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

re-use on a possible following call to curl_easy_perform().

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

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

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.

libcurl will be closed and forgotten.

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

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

repeat curl_easy_perform() call

every repeated \fIcurl_easy_perform()\fP call.