Thu Apr 28 2011 16:57:09

Asterisk developer's documentation


dlinkedlists.h File Reference

A set of macros to manage doubly-linked lists. More...

#include "asterisk/lock.h"
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Defines

#define AST_DLLIST_APPEND_DLLIST(head, list, field)
 Appends a whole list to the tail of a list.
#define AST_DLLIST_EMPTY(head)   (AST_DLLIST_FIRST(head) == NULL)
 Checks whether the specified list contains any entries.
#define AST_DLLIST_ENTRY(type)
 Declare previous/forward links inside a list entry.
#define AST_DLLIST_FIRST(head)   ((head)->first)
 Returns the first entry contained in a list.
#define AST_DLLIST_HEAD(name, type)
 Defines a structure to be used to hold a list of specified type.
#define AST_DLLIST_HEAD_DESTROY(head)
 Destroys a list head structure.
#define AST_DLLIST_HEAD_INIT(head)
 Initializes a list head structure.
#define AST_DLLIST_HEAD_INIT_NOLOCK(head)
 Initializes a list head structure.
#define AST_DLLIST_HEAD_INIT_VALUE
 Defines initial values for a declaration of AST_DLLIST_HEAD.
#define AST_DLLIST_HEAD_NOLOCK(name, type)
 Defines a structure to be used to hold a list of specified type (with no lock).
#define AST_DLLIST_HEAD_NOLOCK_INIT_VALUE
 Defines initial values for a declaration of AST_DLLIST_HEAD_NOLOCK.
#define AST_DLLIST_HEAD_NOLOCK_STATIC(name, type)
 Defines a structure to be used to hold a list of specified type, statically initialized.
#define AST_DLLIST_HEAD_SET(head, entry)
 Initializes a list head structure with a specified first entry.
#define AST_DLLIST_HEAD_SET_NOLOCK(head, entry)
 Initializes a list head structure with a specified first entry.
#define AST_DLLIST_HEAD_STATIC(name, type)
 Defines a structure to be used to hold a list of specified type, statically initialized.
#define AST_DLLIST_INSERT_AFTER(head, listelm, elm, field)
 Inserts a list entry after a given entry.
#define AST_DLLIST_INSERT_BEFORE(head, listelm, elm, field)
 Inserts a list entry before a given entry.
#define AST_DLLIST_INSERT_BEFORE_CURRENT(elm, field)
 Inserts a list entry before the current entry during a traversal.
#define AST_DLLIST_INSERT_BEFORE_CURRENT_BACKWARDS(elm, field)
 Inserts a list entry after the current entry during a backwards traversal. Since this is a backwards traversal, this will insert the entry AFTER the current element. Since this is a backwards traveral, though, this would be BEFORE the current entry in traversal order. Confusing?
#define AST_DLLIST_INSERT_HEAD(head, elm, field)
 Inserts a list entry at the head of a list.
#define AST_DLLIST_INSERT_TAIL(head, elm, field)
 Appends a list entry to the tail of a list.
#define AST_DLLIST_LAST(head)   ((head)->last)
 Returns the last entry contained in a list.
#define AST_DLLIST_LOCK(head)   ast_mutex_lock(&(head)->lock)
 Locks a list.
#define AST_DLLIST_MOVE_CURRENT(newhead, field)
#define AST_DLLIST_MOVE_CURRENT_BACKWARDS(newhead, field)
#define AST_DLLIST_NEXT(elm, field)   ((elm)->field.next)
 Returns the next entry in the list after the given entry.
#define AST_DLLIST_PREV(elm, field)   ((elm)->field.prev)
 Returns the previous entry in the list before the given entry.
#define AST_DLLIST_REMOVE(head, elm, field)
 Removes a specific entry from a list.
#define AST_DLLIST_REMOVE_CURRENT(field)
 Removes the current entry from a list during a traversal.
#define AST_DLLIST_REMOVE_HEAD(head, field)
 Removes and returns the head entry from a list.
#define AST_DLLIST_TRAVERSE(head, var, field)   for((var) = (head)->first; (var); (var) = (var)->field.next)
 Loops over (traverses) the entries in a list.
#define AST_DLLIST_TRAVERSE_BACKWARDS(head, var, field)   for((var) = (head)->last; (var); (var) = (var)->field.prev)
 Loops over (traverses) the entries in a list in reverse order, starting at the end.
#define AST_DLLIST_TRAVERSE_BACKWARDS_SAFE_BEGIN(head, var, field)
 Loops safely over (traverses) the entries in a list.
#define AST_DLLIST_TRAVERSE_BACKWARDS_SAFE_END   }
 Closes a safe loop traversal block.
#define AST_DLLIST_TRAVERSE_SAFE_BEGIN(head, var, field)
 Loops safely over (traverses) the entries in a list.
#define AST_DLLIST_TRAVERSE_SAFE_END   }
 Closes a safe loop traversal block.
#define AST_DLLIST_TRYLOCK(head)   ast_mutex_trylock(&(head)->lock)
 Locks a list, without blocking if the list is locked.
#define AST_DLLIST_UNLOCK(head)   ast_mutex_unlock(&(head)->lock)
 Attempts to unlock a list.
#define AST_RWDLLIST_APPEND_DLLIST   AST_DLLIST_APPEND_DLLIST
#define AST_RWDLLIST_EMPTY   AST_DLLIST_EMPTY
#define AST_RWDLLIST_ENTRY   AST_DLLIST_ENTRY
#define AST_RWDLLIST_FIRST   AST_DLLIST_FIRST
#define AST_RWDLLIST_HEAD(name, type)
 Defines a structure to be used to hold a read/write list of specified type.
#define AST_RWDLLIST_HEAD_DESTROY(head)
 Destroys an rwlist head structure.
#define AST_RWDLLIST_HEAD_INIT(head)
 Initializes an rwlist head structure.
#define AST_RWDLLIST_HEAD_INIT_VALUE
 Defines initial values for a declaration of AST_RWDLLIST_HEAD.
#define AST_RWDLLIST_HEAD_SET(head, entry)
 Initializes an rwlist head structure with a specified first entry.
#define AST_RWDLLIST_HEAD_STATIC(name, type)
 Defines a structure to be used to hold a read/write list of specified type, statically initialized.
#define AST_RWDLLIST_INSERT_AFTER   AST_DLLIST_INSERT_AFTER
#define AST_RWDLLIST_INSERT_BEFORE   AST_DLLIST_INSERT_BEFORE
#define AST_RWDLLIST_INSERT_BEFORE_CURRENT   AST_DLLIST_INSERT_BEFORE_CURRENT
#define AST_RWDLLIST_INSERT_BEFORE_CURRENT_BACKWARDS   AST_DLLIST_INSERT_BEFORE_CURRENT_BACKWARDS
#define AST_RWDLLIST_INSERT_HEAD   AST_DLLIST_INSERT_HEAD
#define AST_RWDLLIST_INSERT_TAIL   AST_DLLIST_INSERT_TAIL
#define AST_RWDLLIST_LAST   AST_DLLIST_LAST
#define AST_RWDLLIST_MOVE_CURRENT   AST_DLLIST_MOVE_CURRENT
#define AST_RWDLLIST_MOVE_CURRENT_BACKWARDS   AST_DLLIST_MOVE_CURRENT
#define AST_RWDLLIST_NEXT   AST_DLLIST_NEXT
#define AST_RWDLLIST_PREV   AST_DLLIST_PREV
#define AST_RWDLLIST_RDLOCK(head)   ast_rwlock_rdlock(&(head)->lock)
 Read locks a list.
#define AST_RWDLLIST_REMOVE   AST_DLLIST_REMOVE
#define AST_RWDLLIST_REMOVE_CURRENT   AST_DLLIST_REMOVE_CURRENT
#define AST_RWDLLIST_REMOVE_HEAD   AST_DLLIST_REMOVE_HEAD
#define AST_RWDLLIST_TRAVERSE   AST_DLLIST_TRAVERSE
#define AST_RWDLLIST_TRAVERSE_BACKWARDS   AST_DLLIST_TRAVERSE_BACKWARDS
#define AST_RWDLLIST_TRAVERSE_BACKWARDS_SAFE_BEGIN   AST_DLLIST_TRAVERSE_BACKWARDS_SAFE_BEGIN
#define AST_RWDLLIST_TRAVERSE_BACKWARDS_SAFE_END   AST_DLLIST_TRAVERSE_BACKWARDS_SAFE_END
#define AST_RWDLLIST_TRAVERSE_SAFE_BEGIN   AST_DLLIST_TRAVERSE_SAFE_BEGIN
#define AST_RWDLLIST_TRAVERSE_SAFE_END   AST_DLLIST_TRAVERSE_SAFE_END
#define AST_RWDLLIST_TRYRDLOCK(head)   ast_rwlock_tryrdlock(&(head)->lock)
 Read locks a list, without blocking if the list is locked.
#define AST_RWDLLIST_TRYWRLOCK(head)   ast_rwlock_trywrlock(&(head)->lock)
 Write locks a list, without blocking if the list is locked.
#define AST_RWDLLIST_UNLOCK(head)   ast_rwlock_unlock(&(head)->lock)
 Attempts to unlock a read/write based list.
#define AST_RWDLLIST_WRLOCK(head)   ast_rwlock_wrlock(&(head)->lock)
 Write locks a list.

Detailed Description

A set of macros to manage doubly-linked lists.

Definition in file dlinkedlists.h.


Define Documentation

#define AST_DLLIST_APPEND_DLLIST (   head,
  list,
  field 
)

Appends a whole list to the tail of a list.

Parameters:
headThis is a pointer to the list head structure
listThis is a pointer to the list to be appended.
fieldThis is the name of the field (declared using AST_DLLIST_ENTRY()) used to link entries of this list together.

Note: The source list (the list parameter) will be empty after calling this macro (the list entries are moved to the target list).

Since:
1.6.1

Definition at line 950 of file dlinkedlists.h.

#define AST_DLLIST_EMPTY (   head)    (AST_DLLIST_FIRST(head) == NULL)

Checks whether the specified list contains any entries.

Parameters:
headThis is a pointer to the list head structure
Returns:
non-zero if the list has entries
zero if not.
Since:
1.6.1

Definition at line 462 of file dlinkedlists.h.

#define AST_DLLIST_ENTRY (   type)
Value:
struct {                      \
   struct type *prev;                  \
   struct type *next;                  \
}

Declare previous/forward links inside a list entry.

Parameters:
typeThis is the type of each list entry.

This macro declares a structure to be used to doubly link list entries together. It must be used inside the definition of the structure named in type, as follows:

  struct list_entry {
   ...
   AST_DLLIST_ENTRY(list_entry) list;
  }

The field name list here is arbitrary, and can be anything you wish.

Since:
1.6.1

Definition at line 406 of file dlinkedlists.h.

#define AST_DLLIST_FIRST (   head)    ((head)->first)

Returns the first entry contained in a list.

Parameters:
headThis is a pointer to the list head structure
Since:
1.6.1

Definition at line 419 of file dlinkedlists.h.

#define AST_DLLIST_HEAD (   name,
  type 
)
Value:
struct name {                       \
   struct type *first;                 \
   struct type *last;                  \
   ast_mutex_t lock;                \
}

Defines a structure to be used to hold a list of specified type.

Parameters:
nameThis will be the name of the defined structure.
typeThis is the type of each list entry.

This macro creates a structure definition that can be used to hold a list of the entries of type type. It does not actually declare (allocate) a structure; to do that, either follow this macro with the desired name of the instance you wish to declare, or use the specified name to declare instances elsewhere.

Example usage:

  static AST_DLLIST_HEAD(entry_list, entry) entries;

This would define struct entry_list, and declare an instance of it named entries, all intended to hold a list of type struct entry.

Since:
1.6.1

Definition at line 157 of file dlinkedlists.h.

#define AST_DLLIST_HEAD_DESTROY (   head)
Value:
{              \
   (head)->first = NULL;                  \
   (head)->last = NULL;                \
   ast_mutex_destroy(&(head)->lock);            \
}

Destroys a list head structure.

Parameters:
headThis is a pointer to the list head structure

This macro destroys a list head structure by setting the head entry to NULL (empty list) and destroying the embedded lock. It does not free the structure from memory.

Since:
1.6.1

Definition at line 812 of file dlinkedlists.h.

#define AST_DLLIST_HEAD_INIT (   head)
Value:
{              \
   (head)->first = NULL;                  \
   (head)->last = NULL;                \
   ast_mutex_init(&(head)->lock);               \
}

Initializes a list head structure.

Parameters:
headThis is a pointer to the list head structure

This macro initializes a list head structure by setting the head entry to NULL (empty list) and recreating the embedded lock.

Since:
1.6.1

Definition at line 783 of file dlinkedlists.h.

#define AST_DLLIST_HEAD_INIT_NOLOCK (   head)
Value:
{           \
   (head)->first = NULL;                  \
   (head)->last = NULL;                \
}

Initializes a list head structure.

Parameters:
headThis is a pointer to the list head structure

This macro initializes a list head structure by setting the head entry to NULL (empty list). There is no embedded lock handling with this macro.

Since:
1.6.1

Definition at line 842 of file dlinkedlists.h.

#define AST_DLLIST_HEAD_INIT_VALUE
Value:
{     \
   .first = NULL,             \
   .last = NULL,              \
   .lock = AST_MUTEX_INIT_VALUE,       \
   }

Defines initial values for a declaration of AST_DLLIST_HEAD.

Since:
1.6.1

Definition at line 221 of file dlinkedlists.h.

#define AST_DLLIST_HEAD_NOLOCK (   name,
  type 
)
Value:
struct name {                       \
   struct type *first;                 \
   struct type *last;                  \
}

Defines a structure to be used to hold a list of specified type (with no lock).

Parameters:
nameThis will be the name of the defined structure.
typeThis is the type of each list entry.

This macro creates a structure definition that can be used to hold a list of the entries of type type. It does not actually declare (allocate) a structure; to do that, either follow this macro with the desired name of the instance you wish to declare, or use the specified name to declare instances elsewhere.

Example usage:

  static AST_DLLIST_HEAD_NOLOCK(entry_list, entry) entries;

This would define struct entry_list, and declare an instance of it named entries, all intended to hold a list of type struct entry.

Since:
1.6.1

Definition at line 211 of file dlinkedlists.h.

#define AST_DLLIST_HEAD_NOLOCK_INIT_VALUE
Value:
{  \
   .first = NULL,             \
   .last = NULL,              \
   }

Defines initial values for a declaration of AST_DLLIST_HEAD_NOLOCK.

Since:
1.6.1

Definition at line 241 of file dlinkedlists.h.

#define AST_DLLIST_HEAD_NOLOCK_STATIC (   name,
  type 
)
Value:
struct name {                       \
   struct type *first;                 \
   struct type *last;                  \
} name = AST_DLLIST_HEAD_NOLOCK_INIT_VALUE

Defines a structure to be used to hold a list of specified type, statically initialized.

This is the same as AST_DLLIST_HEAD_STATIC, except without the lock included.

Since:
1.6.1

Definition at line 338 of file dlinkedlists.h.

#define AST_DLLIST_HEAD_SET (   head,
  entry 
)
Value:
do {           \
   (head)->first = (entry);               \
   (head)->last = (entry);                \
   ast_mutex_init(&(head)->lock);               \
} while (0)

Initializes a list head structure with a specified first entry.

Parameters:
headThis is a pointer to the list head structure
entrypointer to the list entry that will become the head of the list

This macro initializes a list head structure by setting the head entry to the supplied value and recreating the embedded lock.

Since:
1.6.1

Definition at line 353 of file dlinkedlists.h.

#define AST_DLLIST_HEAD_SET_NOLOCK (   head,
  entry 
)
Value:
do {        \
   (head)->first = (entry);               \
   (head)->last = (entry);                \
} while (0)

Initializes a list head structure with a specified first entry.

Parameters:
headThis is a pointer to the list head structure
entrypointer to the list entry that will become the head of the list

This macro initializes a list head structure by setting the head entry to the supplied value.

Since:
1.6.1

Definition at line 383 of file dlinkedlists.h.

#define AST_DLLIST_HEAD_STATIC (   name,
  type 
)
Value:
struct name {                       \
   struct type *first;                 \
   struct type *last;                  \
   ast_mutex_t lock;                \
} name = AST_DLLIST_HEAD_INIT_VALUE

Defines a structure to be used to hold a list of specified type, statically initialized.

Parameters:
nameThis will be the name of the defined structure.
typeThis is the type of each list entry.

This macro creates a structure definition that can be used to hold a list of the entries of type type, and allocates an instance of it, initialized to be empty.

Example usage:

This would define struct entry_list, intended to hold a list of type struct entry.

Since:
1.6.1

Definition at line 281 of file dlinkedlists.h.

#define AST_DLLIST_INSERT_AFTER (   head,
  listelm,
  elm,
  field 
)

Inserts a list entry after a given entry.

Parameters:
headThis is a pointer to the list head structure
listelmThis is a pointer to the entry after which the new entry should be inserted.
elmThis is a pointer to the entry to be inserted.
fieldThis is the name of the field (declared using AST_DLLIST_ENTRY()) used to link entries of this list together.
Since:
1.6.1

Definition at line 857 of file dlinkedlists.h.

#define AST_DLLIST_INSERT_BEFORE (   head,
  listelm,
  elm,
  field 
)

Inserts a list entry before a given entry.

Parameters:
headThis is a pointer to the list head structure
listelmThis is a pointer to the entry before which the new entry should be inserted.
elmThis is a pointer to the entry to be inserted.
fieldThis is the name of the field (declared using AST_DLLIST_ENTRY()) used to link entries of this list together.
Since:
1.6.1

Definition at line 879 of file dlinkedlists.h.

#define AST_DLLIST_INSERT_BEFORE_CURRENT (   elm,
  field 
)

Inserts a list entry before the current entry during a traversal.

Parameters:
elmThis is a pointer to the entry to be inserted.
fieldThis is the name of the field (declared using AST_DLLIST_ENTRY()) used to link entries of this list together.
Note:
This macro can only be used inside an AST_DLLIST_TRAVERSE_SAFE_BEGIN() block.
Since:
1.6.1

Definition at line 712 of file dlinkedlists.h.

#define AST_DLLIST_INSERT_BEFORE_CURRENT_BACKWARDS (   elm,
  field 
)

Inserts a list entry after the current entry during a backwards traversal. Since this is a backwards traversal, this will insert the entry AFTER the current element. Since this is a backwards traveral, though, this would be BEFORE the current entry in traversal order. Confusing?

Parameters:
elmThis is a pointer to the entry to be inserted.
fieldThis is the name of the field (declared using AST_DLLIST_ENTRY()) used to link entries of this list together.
Note:
This macro can only be used inside an AST_DLLIST_TRAVERSE_BACKWARDS_SAFE_BEGIN() block. If you use this with the AST_DLLIST_TRAVERSE_SAFE_BEGIN(), be prepared for strange things!
Since:
1.6.1

Definition at line 743 of file dlinkedlists.h.

#define AST_DLLIST_INSERT_HEAD (   head,
  elm,
  field 
)

Inserts a list entry at the head of a list.

Parameters:
headThis is a pointer to the list head structure
elmThis is a pointer to the entry to be inserted.
fieldThis is the name of the field (declared using AST_DLLIST_ENTRY()) used to link entries of this list together.
Since:
1.6.1

Definition at line 899 of file dlinkedlists.h.

#define AST_DLLIST_INSERT_TAIL (   head,
  elm,
  field 
)

Appends a list entry to the tail of a list.

Parameters:
headThis is a pointer to the list head structure
elmThis is a pointer to the entry to be appended.
fieldThis is the name of the field (declared using AST_DLLIST_ENTRY()) used to link entries of this list together.

Note: The link field in the appended entry is not modified, so if it is actually the head of a list itself, the entire list will be appended temporarily (until the next AST_DLLIST_INSERT_TAIL is performed).

Since:
1.6.1

Definition at line 923 of file dlinkedlists.h.

#define AST_DLLIST_LAST (   head)    ((head)->last)

Returns the last entry contained in a list.

Parameters:
headThis is a pointer to the list head structure
Since:
1.6.1

Definition at line 428 of file dlinkedlists.h.

#define AST_DLLIST_LOCK (   head)    ast_mutex_lock(&(head)->lock)

Locks a list.

Parameters:
headThis is a pointer to the list head structure

This macro attempts to place an exclusive lock in the list head structure pointed to by head.

Return values:
0on success
non-zeroon failure
Since:
1.6.1

Definition at line 45 of file dlinkedlists.h.

#define AST_DLLIST_MOVE_CURRENT (   newhead,
  field 
)
Value:
do { \
   typeof ((newhead)->first) __list_cur = __new_prev;          \
   AST_DLLIST_REMOVE_CURRENT(field);                     \
   AST_DLLIST_INSERT_TAIL((newhead), __list_cur, field);          \
   } while (0)

Definition at line 681 of file dlinkedlists.h.

#define AST_DLLIST_MOVE_CURRENT_BACKWARDS (   newhead,
  field 
)

Definition at line 689 of file dlinkedlists.h.

#define AST_DLLIST_NEXT (   elm,
  field 
)    ((elm)->field.next)

Returns the next entry in the list after the given entry.

Parameters:
elmThis is a pointer to the current entry.
fieldThis is the name of the field (declared using AST_DLLIST_ENTRY()) used to link entries of this list together.
Since:
1.6.1

Definition at line 439 of file dlinkedlists.h.

#define AST_DLLIST_PREV (   elm,
  field 
)    ((elm)->field.prev)

Returns the previous entry in the list before the given entry.

Parameters:
elmThis is a pointer to the current entry.
fieldThis is the name of the field (declared using AST_DLLIST_ENTRY()) used to link entries of this list together.
Since:
1.6.1

Definition at line 450 of file dlinkedlists.h.

#define AST_DLLIST_REMOVE (   head,
  elm,
  field 
)

Removes a specific entry from a list.

Parameters:
headThis is a pointer to the list head structure
elmThis is a pointer to the entry to be removed.
fieldThis is the name of the field (declared using AST_DLLIST_ENTRY()) used to link entries of this list together.
Warning:
The removed entry is not freed nor modified in any way.
Since:
1.6.1

Definition at line 999 of file dlinkedlists.h.

Referenced by ast_event_unsubscribe().

#define AST_DLLIST_REMOVE_CURRENT (   field)

Removes the current entry from a list during a traversal.

Parameters:
fieldThis is the name of the field (declared using AST_DLLIST_ENTRY()) used to link entries of this list together.
Note:
This macro can only be used inside an AST_DLLIST_TRAVERSE_SAFE_BEGIN() block; it is used to unlink the current entry from the list without affecting the list traversal (and without having to re-traverse the list to modify the previous entry, if any).
Since:
1.6.1

Definition at line 659 of file dlinkedlists.h.

#define AST_DLLIST_REMOVE_HEAD (   head,
  field 
)

Removes and returns the head entry from a list.

Parameters:
headThis is a pointer to the list head structure
fieldThis is the name of the field (declared using AST_DLLIST_ENTRY()) used to link entries of this list together.

Removes the head entry from the list, and returns a pointer to it. This macro is safe to call on an empty list.

Since:
1.6.1

Definition at line 975 of file dlinkedlists.h.

#define AST_DLLIST_TRAVERSE (   head,
  var,
  field 
)    for((var) = (head)->first; (var); (var) = (var)->field.next)

Loops over (traverses) the entries in a list.

Parameters:
headThis is a pointer to the list head structure
varThis is the name of the variable that will hold a pointer to the current list entry on each iteration. It must be declared before calling this macro.
fieldThis is the name of the field (declared using AST_DLLIST_ENTRY()) used to link entries of this list together.

This macro is use to loop over (traverse) the entries in a list. It uses a for loop, and supplies the enclosed code with a pointer to each list entry as it loops. It is typically used as follows:

  static AST_DLLIST_HEAD(entry_list, list_entry) entries;
  ...
  struct list_entry {
   ...
   AST_DLLIST_ENTRY(list_entry) list;
  }
  ...
  struct list_entry *current;
  ...
  AST_DLLIST_TRAVERSE(&entries, current, list) {
     (do something with current here)
  }
Warning:
If you modify the forward-link pointer contained in the current entry while inside the loop, the behavior will be unpredictable. At a minimum, the following macros will modify the forward-link pointer, and should not be used inside AST_DLLIST_TRAVERSE() against the entry pointed to by the current pointer without careful consideration of their consequences:
Since:
1.6.1

Definition at line 503 of file dlinkedlists.h.

#define AST_DLLIST_TRAVERSE_BACKWARDS (   head,
  var,
  field 
)    for((var) = (head)->last; (var); (var) = (var)->field.prev)

Loops over (traverses) the entries in a list in reverse order, starting at the end.

Parameters:
headThis is a pointer to the list head structure
varThis is the name of the variable that will hold a pointer to the current list entry on each iteration. It must be declared before calling this macro.
fieldThis is the name of the field (declared using AST_DLLIST_ENTRY()) used to link entries of this list together.

This macro is use to loop over (traverse) the entries in a list in reverse order. It uses a for loop, and supplies the enclosed code with a pointer to each list entry as it loops. It is typically used as follows:

  static AST_DLLIST_HEAD(entry_list, list_entry) entries;
  ...
  struct list_entry {
   ...
   AST_DLLIST_ENTRY(list_entry) list;
  }
  ...
  struct list_entry *current;
  ...
  AST_DLLIST_TRAVERSE_BACKWARDS(&entries, current, list) {
     (do something with current here)
  }
Warning:
If you modify the forward-link pointer contained in the current entry while inside the loop, the behavior will be unpredictable. At a minimum, the following macros will modify the forward-link pointer, and should not be used inside AST_DLLIST_TRAVERSE() against the entry pointed to by the current pointer without careful consideration of their consequences:
Since:
1.6.1

Definition at line 545 of file dlinkedlists.h.

#define AST_DLLIST_TRAVERSE_BACKWARDS_SAFE_BEGIN (   head,
  var,
  field 
)

Loops safely over (traverses) the entries in a list.

Parameters:
headThis is a pointer to the list head structure
varThis is the name of the variable that will hold a pointer to the current list entry on each iteration. It must be declared before calling this macro.
fieldThis is the name of the field (declared using AST_DLLIST_ENTRY()) used to link entries of this list together.

This macro is used to safely loop over (traverse) the entries in a list. It uses a for loop, and supplies the enclosed code with a pointer to each list entry as it loops. It is typically used as follows:

  static AST_DLLIST_HEAD(entry_list, list_entry) entries;
  ...
  struct list_entry {
   ...
   AST_DLLIST_ENTRY(list_entry) list;
  }
  ...
  struct list_entry *current;
  ...
  AST_DLLIST_TRAVERSE_SAFE_BEGIN(&entries, current, list) {
     (do something with current here)
  }
  AST_DLLIST_TRAVERSE_SAFE_END;

It differs from AST_DLLIST_TRAVERSE() in that the code inside the loop can modify (or even free, after calling AST_DLLIST_REMOVE_CURRENT()) the entry pointed to by the current pointer without affecting the loop traversal.

Since:
1.6.1

Definition at line 633 of file dlinkedlists.h.

#define AST_DLLIST_TRAVERSE_BACKWARDS_SAFE_END   }

Closes a safe loop traversal block.

Since:
1.6.1

Definition at line 771 of file dlinkedlists.h.

#define AST_DLLIST_TRAVERSE_SAFE_BEGIN (   head,
  var,
  field 
)

Loops safely over (traverses) the entries in a list.

Parameters:
headThis is a pointer to the list head structure
varThis is the name of the variable that will hold a pointer to the current list entry on each iteration. It must be declared before calling this macro.
fieldThis is the name of the field (declared using AST_DLLIST_ENTRY()) used to link entries of this list together.

This macro is used to safely loop over (traverse) the entries in a list. It uses a for loop, and supplies the enclosed code with a pointer to each list entry as it loops. It is typically used as follows:

  static AST_DLLIST_HEAD(entry_list, list_entry) entries;
  ...
  struct list_entry {
   ...
   AST_DLLIST_ENTRY(list_entry) list;
  }
  ...
  struct list_entry *current;
  ...
  AST_DLLIST_TRAVERSE_SAFE_BEGIN(&entries, current, list) {
     (do something with current here)
  }
  AST_DLLIST_TRAVERSE_SAFE_END;

It differs from AST_DLLIST_TRAVERSE() in that the code inside the loop can modify (or even free, after calling AST_DLLIST_REMOVE_CURRENT()) the entry pointed to by the current pointer without affecting the loop traversal.

Since:
1.6.1

Definition at line 584 of file dlinkedlists.h.

#define AST_DLLIST_TRAVERSE_SAFE_END   }

Closes a safe loop traversal block.

Since:
1.6.1

Definition at line 763 of file dlinkedlists.h.

#define AST_DLLIST_TRYLOCK (   head)    ast_mutex_trylock(&(head)->lock)

Locks a list, without blocking if the list is locked.

Parameters:
headThis is a pointer to the list head structure

This macro attempts to place an exclusive lock in the list head structure pointed to by head.

Return values:
0on success
non-zeroon failure
Since:
1.6.1

Definition at line 84 of file dlinkedlists.h.

#define AST_DLLIST_UNLOCK (   head)    ast_mutex_unlock(&(head)->lock)

Attempts to unlock a list.

Parameters:
headThis is a pointer to the list head structure

This macro attempts to remove an exclusive lock from the list head structure pointed to by head. If the list was not locked by this thread, this macro has no effect.

Since:
1.6.1

Definition at line 122 of file dlinkedlists.h.

#define AST_RWDLLIST_APPEND_DLLIST   AST_DLLIST_APPEND_DLLIST

Definition at line 963 of file dlinkedlists.h.

#define AST_RWDLLIST_EMPTY   AST_DLLIST_EMPTY

Definition at line 464 of file dlinkedlists.h.

#define AST_RWDLLIST_ENTRY   AST_DLLIST_ENTRY

Definition at line 412 of file dlinkedlists.h.

#define AST_RWDLLIST_FIRST   AST_DLLIST_FIRST

Definition at line 421 of file dlinkedlists.h.

#define AST_RWDLLIST_HEAD (   name,
  type 
)
Value:
struct name {                                                           \
        struct type *first;                                             \
        struct type *last;                                              \
        ast_rwlock_t lock;                                              \
}

Defines a structure to be used to hold a read/write list of specified type.

Parameters:
nameThis will be the name of the defined structure.
typeThis is the type of each list entry.

This macro creates a structure definition that can be used to hold a list of the entries of type type. It does not actually declare (allocate) a structure; to do that, either follow this macro with the desired name of the instance you wish to declare, or use the specified name to declare instances elsewhere.

Example usage:

  static AST_RWDLLIST_HEAD(entry_list, entry) entries;

This would define struct entry_list, and declare an instance of it named entries, all intended to hold a list of type struct entry.

Since:
1.6.1

Definition at line 184 of file dlinkedlists.h.

#define AST_RWDLLIST_HEAD_DESTROY (   head)
Value:
{                                 \
        (head)->first = NULL;                                           \
        (head)->last = NULL;                                            \
        ast_rwlock_destroy(&(head)->lock);                              \
}

Destroys an rwlist head structure.

Parameters:
headThis is a pointer to the list head structure

This macro destroys a list head structure by setting the head entry to NULL (empty list) and destroying the embedded lock. It does not free the structure from memory.

Since:
1.6.1

Definition at line 827 of file dlinkedlists.h.

#define AST_RWDLLIST_HEAD_INIT (   head)
Value:
{                                    \
        (head)->first = NULL;                                           \
        (head)->last = NULL;                                            \
        ast_rwlock_init(&(head)->lock);                                 \
}

Initializes an rwlist head structure.

Parameters:
headThis is a pointer to the list head structure

This macro initializes a list head structure by setting the head entry to NULL (empty list) and recreating the embedded lock.

Since:
1.6.1

Definition at line 797 of file dlinkedlists.h.

Referenced by ast_event_init().

#define AST_RWDLLIST_HEAD_INIT_VALUE
Value:
{               \
        .first = NULL,                                  \
        .last = NULL,                                   \
        .lock = AST_RWLOCK_INIT_VALUE,                  \
        }

Defines initial values for a declaration of AST_RWDLLIST_HEAD.

Since:
1.6.1

Definition at line 231 of file dlinkedlists.h.

#define AST_RWDLLIST_HEAD_SET (   head,
  entry 
)
Value:
do {                           \
        (head)->first = (entry);                                        \
        (head)->last = (entry);                                         \
        ast_rwlock_init(&(head)->lock);                                 \
} while (0)

Initializes an rwlist head structure with a specified first entry.

Parameters:
headThis is a pointer to the list head structure
entrypointer to the list entry that will become the head of the list

This macro initializes a list head structure by setting the head entry to the supplied value and recreating the embedded lock.

Since:
1.6.1

Definition at line 368 of file dlinkedlists.h.

#define AST_RWDLLIST_HEAD_STATIC (   name,
  type 
)

Defines a structure to be used to hold a read/write list of specified type, statically initialized.

Parameters:
nameThis will be the name of the defined structure.
typeThis is the type of each list entry.

This macro creates a structure definition that can be used to hold a list of the entries of type type, and allocates an instance of it, initialized to be empty.

Example usage:

This would define struct entry_list, intended to hold a list of type struct entry.

Since:
1.6.1

Definition at line 308 of file dlinkedlists.h.

#define AST_RWDLLIST_INSERT_AFTER   AST_DLLIST_INSERT_AFTER

Definition at line 867 of file dlinkedlists.h.

#define AST_RWDLLIST_INSERT_BEFORE   AST_DLLIST_INSERT_BEFORE

Definition at line 889 of file dlinkedlists.h.

#define AST_RWDLLIST_INSERT_BEFORE_CURRENT   AST_DLLIST_INSERT_BEFORE_CURRENT

Definition at line 727 of file dlinkedlists.h.

#define AST_RWDLLIST_INSERT_BEFORE_CURRENT_BACKWARDS   AST_DLLIST_INSERT_BEFORE_CURRENT_BACKWARDS

Definition at line 757 of file dlinkedlists.h.

#define AST_RWDLLIST_INSERT_HEAD   AST_DLLIST_INSERT_HEAD

Definition at line 909 of file dlinkedlists.h.

#define AST_RWDLLIST_INSERT_TAIL   AST_DLLIST_INSERT_TAIL

Definition at line 937 of file dlinkedlists.h.

Referenced by ast_event_sub_activate().

#define AST_RWDLLIST_LAST   AST_DLLIST_LAST

Definition at line 430 of file dlinkedlists.h.

#define AST_RWDLLIST_MOVE_CURRENT   AST_DLLIST_MOVE_CURRENT

Definition at line 687 of file dlinkedlists.h.

#define AST_RWDLLIST_MOVE_CURRENT_BACKWARDS   AST_DLLIST_MOVE_CURRENT

Definition at line 700 of file dlinkedlists.h.

#define AST_RWDLLIST_NEXT   AST_DLLIST_NEXT

Definition at line 441 of file dlinkedlists.h.

#define AST_RWDLLIST_PREV   AST_DLLIST_PREV

Definition at line 452 of file dlinkedlists.h.

#define AST_RWDLLIST_RDLOCK (   head)    ast_rwlock_rdlock(&(head)->lock)

Read locks a list.

Parameters:
headThis is a pointer to the list head structure

This macro attempts to place a read lock in the list head structure pointed to by head.

Return values:
0on success
non-zeroon failure
Since:
1.6.1

Definition at line 71 of file dlinkedlists.h.

Referenced by ast_event_check_subscriber(), ast_event_report_subs(), and handle_event().

#define AST_RWDLLIST_REMOVE   AST_DLLIST_REMOVE

Definition at line 1019 of file dlinkedlists.h.

#define AST_RWDLLIST_REMOVE_CURRENT   AST_DLLIST_REMOVE_CURRENT

Definition at line 679 of file dlinkedlists.h.

#define AST_RWDLLIST_REMOVE_HEAD   AST_DLLIST_REMOVE_HEAD

Definition at line 988 of file dlinkedlists.h.

#define AST_RWDLLIST_TRAVERSE   AST_DLLIST_TRAVERSE

Definition at line 506 of file dlinkedlists.h.

Referenced by ast_event_check_subscriber(), ast_event_report_subs(), and handle_event().

#define AST_RWDLLIST_TRAVERSE_BACKWARDS   AST_DLLIST_TRAVERSE_BACKWARDS

Definition at line 548 of file dlinkedlists.h.

#define AST_RWDLLIST_TRAVERSE_BACKWARDS_SAFE_BEGIN   AST_DLLIST_TRAVERSE_BACKWARDS_SAFE_BEGIN

Definition at line 646 of file dlinkedlists.h.

#define AST_RWDLLIST_TRAVERSE_BACKWARDS_SAFE_END   AST_DLLIST_TRAVERSE_BACKWARDS_SAFE_END

Definition at line 773 of file dlinkedlists.h.

#define AST_RWDLLIST_TRAVERSE_SAFE_BEGIN   AST_DLLIST_TRAVERSE_SAFE_BEGIN

Definition at line 597 of file dlinkedlists.h.

#define AST_RWDLLIST_TRAVERSE_SAFE_END   AST_DLLIST_TRAVERSE_SAFE_END

Definition at line 765 of file dlinkedlists.h.

#define AST_RWDLLIST_TRYRDLOCK (   head)    ast_rwlock_tryrdlock(&(head)->lock)

Read locks a list, without blocking if the list is locked.

Parameters:
headThis is a pointer to the list head structure

This macro attempts to place a read lock in the list head structure pointed to by head.

Return values:
0on success
non-zeroon failure
Since:
1.6.1

Definition at line 110 of file dlinkedlists.h.

#define AST_RWDLLIST_TRYWRLOCK (   head)    ast_rwlock_trywrlock(&(head)->lock)

Write locks a list, without blocking if the list is locked.

Parameters:
headThis is a pointer to the list head structure

This macro attempts to place an exclusive write lock in the list head structure pointed to by head.

Return values:
0on success
non-zeroon failure
Since:
1.6.1

Definition at line 97 of file dlinkedlists.h.

#define AST_RWDLLIST_UNLOCK (   head)    ast_rwlock_unlock(&(head)->lock)

Attempts to unlock a read/write based list.

Parameters:
headThis is a pointer to the list head structure

This macro attempts to remove a read or write lock from the list head structure pointed to by head. If the list was not locked by this thread, this macro has no effect.

Since:
1.6.1

Definition at line 134 of file dlinkedlists.h.

Referenced by ast_event_check_subscriber(), ast_event_report_subs(), ast_event_sub_activate(), ast_event_unsubscribe(), and handle_event().

#define AST_RWDLLIST_WRLOCK (   head)    ast_rwlock_wrlock(&(head)->lock)

Write locks a list.

Parameters:
headThis is a pointer to the list head structure

This macro attempts to place an exclusive write lock in the list head structure pointed to by head.

Return values:
0on success
non-zeroon failure
Since:
1.6.1

Definition at line 58 of file dlinkedlists.h.

Referenced by ast_event_sub_activate(), and ast_event_unsubscribe().