View source for Hacker Guide/Access

== Description  ==

The modules of ''''access'''' capability are designed to be the first and last elements of a modules chain.

Access [[Documentation:Hacker's Guide/Access|input]] and [[Documentation:Hacker's Guide/Access output|output]] handles most of the basic '''I/O''' for VLC. They are usually '''protocols''' implementations (http, ftp,...) or '''devices''' access (Webcams, Capture cards).

We will discuss about ''''input access'''' in this page.

== Writing an access module ==

To write an access module, read the [[Documentation:Hacker's_Guide/Module_Writers_Guide|introduction to module writing]].

Then, you should specify your module of being of access type:
 set_capability( "access", 60 )  
 set_category( CAT_INPUT )                                                                                                                                                                                  
 set_subcategory( SUBCAT_INPUT_ACCESS )   

                                                                                                                                                                  
== Functionality  ==

Generally speaking, [[Documentation:Hacker's Guide/Access|access input]] will provide Read() functions and [[Documentation:Hacker's Guide/Access output|output]] Write(). 

Both needs to provide Seek() and Control() even if the underlying architecture does not support these actions. In this case, Seek() and Control() should return VLC_EGENERIC, although Control() might need to answer ACCESS_OUT_CONTROLS_PACE requests. See modules/access_output/http.c about using a source without seeking.