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TSEARCH(3) BSD Library Functions Manual TSEARCH(3)
NAME
tsearch, tfind, tdelete, twalk -- manipulate binary search trees
SYNOPSIS
#include <search.h>
void *
tdelete(const void *key, void **rootp, int (*compar) (const void *, const void *));
void *
tfind(const void *key, void **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 (*compar) (const void *, VISIT, int));
DESCRIPTION
The 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 traver-
sal type, and a node level (where level zero is the root of the tree).
SEE ALSO
bsearch(3), hsearch(3), lsearch(3)
RETURN VALUES
The 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.
BSD June 15, 1997 BSD
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