TSEARCH(3) BSD Programmer's 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 * 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));
DESCRIPTION
The tdelete(), tfind(), tsearch(), and twalk() functions manage binary
search trees based on algorithms T and D from Knuth (6.2.2). The com-
parison 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 re-
turns 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 func-
tion 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).
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 da-
tum cannot be found.
The twalk() function returns no value.
SEE ALSObsearch(3), lsearch(3)MirOS BSD #10-current June 15, 1997 1
