Difference between pages "r6:Function:slist query" and "r6:Function:slist set user data in element"

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==Source Files==
==Source Files==
  /src/slist/slist_query.c
  /src/slist/slist_get_and_set.c
  /inc/liblfds.h
  /inc/liblfds.h
==Enums==
enum slist_query_type
{
  SLIST_QUERY_VALIDATE
};


==Prototype==
==Prototype==
  void slist_query( struct slist_state *ss, enum slist_query_type query_type, void *query_input, void *query_output );
  int slist_set_user_data_in_element( struct slist_element *se, void *user_data );


==Parameters==
==Parameters==
''struct slist_state *ss''
''struct slist_element *se''
: An slist state as allocated by ''[[r6:Function:slist_new|slist_new]]''.
: A pointer to an slist element as allocated by ''[[r6:Function:slist_new_head|slist_new_head]]'' or ''[[r6:Function:slist_new_next|slist_new_next]]''.
 
''enum slist_query_type query_type''
: Indicates which query to perform.
 
''void *query_input''
: A pointer to data, or data cast to a void pointer, which is input data required by requested query.  Only some queries require input data.  If no input data is required, set query_input to NULL.


''void *query_output''
''void *user_data''
: The address of a variable into which the requested information is placed.  The type of variable varies on the type of query; see Notes.
: A void pointer of user data which will be placed into the slist element.


==Return Value==
==Return Value==
No return value.  The variable pointed to by ''query_output'' (the type of which will vary depending on the query, see Notes) will be set; this is the mechanism by which information is passed back to the caller.  Currently, no query can fail, so there is no notion of an error value.
Returns 1 on success, 0 on failure.  The only cause of failure is if you try to set the user data in an element which has been logically deleted.


==Notes==
==Notes==
The following query is currently supported;
This function sets the user data void pointer in the slist element.
 
* SLIST_QUERY_VALIDITY
** ''query_input'' may be NULL or may point to a ''struct validation_info''.  This structure contains the minimum and maximum expected number of elements currently held in the ringbuffer (set minimum and maximum to the same value if the exact value is known).  The expected minimum and maximum number of elements in the queue, the queue's freelist and the ringbuffer's freelist can all be derived from the original numbers, since the queue begins empty and the initial number of elements in the freelist is known.  If NULL, no check for missing or additional elements is performed.
** ''query_output'' must point to an an array of three ''enum data_structure_validity''.  The validation check detects loops, missing elements and additional elements in the queue, the queue's freelist and the ringbuffer's freelist and sets the values of query_output accordingly.  The first element in the array is used for the queue's validity state, the second for the queue's freelist's validity state, the third for the ringbuffer's freelist's validity state  The main purpose of this query is to provide a validation function to the test program.


==See Also==
==See Also==
* [[r6:API:SList|SList]]
* [[r6:API:SList|SList]]
* [[r6:Function:slist_get_user_data_from_element|slist_get_user_data_from_element]]

Latest revision as of 14:07, 4 January 2015

Source Files

/src/slist/slist_get_and_set.c
/inc/liblfds.h

Prototype

int slist_set_user_data_in_element( struct slist_element *se, void *user_data );

Parameters

struct slist_element *se

A pointer to an slist element as allocated by slist_new_head or slist_new_next.

void *user_data

A void pointer of user data which will be placed into the slist element.

Return Value

Returns 1 on success, 0 on failure. The only cause of failure is if you try to set the user data in an element which has been logically deleted.

Notes

This function sets the user data void pointer in the slist element.

See Also