Difference between revisions of "Hacker Guide/Variables"
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It can be compared to an [http://en.wikipedia.org/wiki/Observer_pattern Observer Pattern]. | It can be compared to an [http://en.wikipedia.org/wiki/Observer_pattern Observer Pattern]. | ||
| + | |||
| + | <font color="red" size="30px">WARNING: page under construction</font> | ||
== Variable Functions == | == Variable Functions == | ||
| − | === var_Get === | + | === var_Get === |
| − | '''va_Get*''' functions will get the value if the variable exists (and will error otherwise). | + | '''va_Get*''' functions will get the value if the variable exists (and will error otherwise). |
var_Get ( vlc_object_t *, const char *, vlc_value_t * ); | var_Get ( vlc_object_t *, const char *, vlc_value_t * ); | ||
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var_GetAddress( p_obj, psz_name ); | var_GetAddress( p_obj, psz_name ); | ||
| − | === var_Inherit === | + | === var_Inherit === |
| − | '''var_Inherit*''' functions will get the default value (from configuration, for example) or the one set by the parent object. | + | |
| + | '''var_Inherit*''' functions will get the default value (from configuration, for example) or the one set by the parent object. | ||
| + | |||
var_Inherit | var_Inherit | ||
var_InheritBool | var_InheritBool | ||
| Line 31: | Line 35: | ||
var_InheritURational | var_InheritURational | ||
| − | === var_CreateGet === | + | === var_CreateGet === |
| − | '''var_CreateGet*''' functions will create the variable and the get the default value if the variable wasn't already created. | + | |
| + | '''var_CreateGet*''' functions will create the variable and the get the default value if the variable wasn't already created. | ||
If the variable does exist before the call it will get the current value (and increment its [http://en.wikipedia.org/wiki/Refcount refcount]). | If the variable does exist before the call it will get the current value (and increment its [http://en.wikipedia.org/wiki/Refcount refcount]). | ||
Revision as of 21:20, 21 March 2011
Introduction
VLC media player has a powerful "object variable" infrastructure, that can be used to pass information between modules.
It can be compared to an Observer Pattern.
WARNING: page under construction
Variable Functions
var_Get
va_Get* functions will get the value if the variable exists (and will error otherwise).
var_Get ( vlc_object_t *, const char *, vlc_value_t * ); var_GetBool( p_obj, psz_name ); var_GetInteger( p_obj, psz_name ); var_GetTime( p_obj, psz_name ); var_GetFloat( p_obj, psz_name ); var_GetString( p_obj, psz_name ); var_GetNonEmptyString( p_obj, psz_name ); var_GetAddress( p_obj, psz_name );
var_Inherit
var_Inherit* functions will get the default value (from configuration, for example) or the one set by the parent object.
var_Inherit var_InheritBool var_InheritInteger var_InheritFloat var_InheritString var_InheritTime var_InheritAddress var_InheritURational
var_CreateGet
var_CreateGet* functions will create the variable and the get the default value if the variable wasn't already created.
If the variable does exist before the call it will get the current value (and increment its refcount).
var_Create(a,b,c) var_CreateGetInteger(a,b) var_CreateGetBool(a,b) var_CreateGetTime(a,b) var_CreateGetFloat(a,b) var_CreateGetString(a,b) var_CreateGetNonEmptyString(a,b) var_CreateGetAddress(a,b) var_CreateGetIntegerCommand(a,b) var_CreateGetBoolCommand(a,b) var_CreateGetTimeCommand(a,b) var_CreateGetFloatCommand(a,b) var_CreateGetStringCommand(a,b) var_CreateGetNonEmptyStringCommand(a,b)
A variable must be created if you want to add a callback or change the value (with var_Set) of a variable
