| TSEARCH(3) | Library Functions Manual | TSEARCH(3) | 
tsearch, tfind, tdelete, twalk —
#include <search.h>
void *
  
  tdelete(const
    void * restrict key, void
    ** restrict rootp, int
    (*compar) (const void *, const void *));
void *
  
  tfind(const
    void *key, const void *
    const *rootp, int
    (*compar) (const void *, const void *));
void *
  
  tsearch(const
    void *key, void
    **rootp, int (*compar)
    (const void *, const void *));
void
  
  twalk(const
    void *root, void
    (*action) (const void *, VISIT, int));
tdelete(), tfind(),
  tsearch(), and twalk()
  functions manage binary search trees based on algorithms T and D from Knuth
  (6.2.2). The comparison function passed in by the user has the same style of
  return values as strcmp(3).
tfind() searches for the datum matched by
    the argument key in the binary tree rooted at
    rootp, returning a pointer to the datum if it is found
    and NULL if it is not.
tsearch() is identical to
    tfind() except that if no match is found,
    key is inserted into the tree and a pointer to it is
    returned. If rootp points to a NULL value a new binary
    search tree is created.
tdelete() deletes a node from the
    specified binary search tree and returns a pointer to the parent of the node
    to be deleted. It takes the same arguments as
    tfind() and tsearch(). If
    the node to be deleted is the root of the binary search tree,
    rootp will be adjusted.
twalk() walks the binary search tree
    rooted in root and calls the function
    action on each node. Action is
    called with three arguments: a pointer to the current node, a value from the
    enum typedef enum { preorder, postorder, endorder, leaf }
    VISIT; specifying the traversal type, and a node level (where level zero
    is the root of the tree).
tsearch() function returns NULL if allocation of a
  new node fails (usually due to a lack of free memory).
tfind(),
    tsearch(), and tdelete()
    return NULL if rootp is NULL or the datum cannot be
    found.
The twalk() function returns no value.
tdelete()
  should not rely on any specific behaviour. The IEEE Std
  1003.1-2008 (“POSIX.1”) revision tried to clarify the
  issue with the following wording: “the
  tdelete() function shall return a pointer to the
  parent of the deleted node, or an unspecified non-NULL pointer if the deleted
  node was the root node, or a NULL pointer if the node
  is not found”.
| April 30, 2010 | NetBSD 9.4 |