Difference between revisions of "Code Conventions"

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== Qt interface added conventions ==
== Qt interface added conventions ==
:'''''See [http://git.videolan.org/?p=vlc.git;a=blob;f=modules/gui/qt4/HACKING HACKING]'''''
:'''''See [http://git.videolan.org/?p=vlc.git;a=blob;f=modules/gui/qt/HACKING HACKING]'''''

Revision as of 23:43, 6 February 2017


The following conventions are the 'classical' VLC code conventions. Those are not enforced anymore.

The important is to keep consistency of codestyle when you modify a file.

If you write a new file, select your style. Common used styles are VLC Style and K&R.

Code conventions

Here you find conventions about how the VLC media player developers write their code.

Function naming

All functions are named accordingly: module name (in lower case) + _ + function name (in mixed case, without underscores). For instance: intf_FooFunction. Static functions don't need the module name.

Variable naming

We use Hungarian notation. That is, we have the following prefixes:

  • i_ for integers (sometimes l_ for long integers)
  • b_ for booleans
  • d_ for doubles
  • f_ for floats
  • Generally, we add a p when the variable is a pointer to a type
    • pf_ for function pointers
    • psz_ for a pointer to a string terminated by a zero (C-string)

If a variable has no basic type (for instance a complex structure), don't put any prefix (except p_ if it's a pointer). After one prefix, put an explicit variable name in lower case. If several words are required, join them with an underscore (no mixed case).


  • data_packet_t * p_buffer
  • char psz_msg_date[42]
  • int pi_es_refcount[MAX_ES];
  • void (* pf_next_data_packet)( int * )

A few words about white space


Never use tabs in the source (nevertheless you're entitled to use them in the Makefile :-).

Use set expandtab under vim or the equivalent under emacs.

Indents are 4 spaces long.


Put spaces before and after operators, and inside brackets. For instance:

for( i = 0; i < 12; i++, j += 42 ); 


Leave braces alone on their lines (GNU style[1]). For instance:

if( i_es == 42 )
   p_buffer[0] = 0x12;


ANSI C-style comments /* ... */ are more commonly used for historical reasons, though C++/C99 comments are tolerated, but please don't mix both in the same file.

Qt interface added conventions