Flickcurl is a C library for the Flickr API, handling creating the requests,
signing, token management, calling the API, marshalling request parameters
and decoding responses.  It uses libcurl to call the REST web service and
libxml2 to manipulate the XML responses.  The current version supports part
of the API (see Flickcurl API coverage) primarily the functions for reading
photo, people and tags description, uploading photos, changing tags and
comments.

WWW: http://librdf.org/flickcurl/