curl / libcurl / API

The libcurl API

Read the libcurl tutorial to get a general in-depth grip of what libcurl programming is all about.

There are some example C source codes you can check out.

Dig into the Symbols In Versions document to learn in which libcurl releases symbols were added or removed.

Easy or Multi

The easy interface is a synchronous, efficient, quickly used and... yes, easy interface for file transfers. Numerous applications have been built using this.

The multi interface is the asynchronous brother in the family and it also offers multiple transfers using a single thread and more. Get a grip of how to work with it in the multi interface overview.

The Easy interface

When using libcurl you init your easy-session and get a handle, which you use as input to the following interface functions you use.

You continue by setting all the options you want in the upcoming transfer, most important among them is the URL itself. You might want to set some callbacks as well that will be called from the library when data is available etc.

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

After the performance is made, you may get information about the transfer and then you cleanup the easy-session's handle and libcurl is entirely off the hook!

See also the easy interface overview.


While the above functions are the main functions to use in the easy interface, there is a series of other helpful functions too including:

curl_version() returns a pointer to the libcurl version string
curl_getdate() converts a date string to time_t
curl_mime_init() ... and family, to build multipart form-data posts
curl_formadd() (old-style) build multipart form-data posts
curl_slist_append() builds a linked list
curl_slist_free_all() frees a whole curl_slist as made with curl_slist_append()
curl_easy_escape() URL encodes a string
curl_easy_unescape() URL decodes a string

All man pages are also included in every release archive.