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TSEARCH(3)            DragonFly Library Functions Manual            TSEARCH(3)


NAME

     tsearch, tfind, tdelete, twalk -- manipulate binary search trees


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

     #include <search.h>

     void *
     tdelete(const void * restrict key, void ** restrict 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 compar-
     ison function passed in by the user has the same style of return values
     as strcmp(3).

     The tfind() function 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.

     The tsearch() function 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.

     The tdelete() function 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.

     The twalk() function walks the binary search tree rooted in root and
     calls the function action on each node.  The action function is called
     with three arguments: a pointer to the current node, a value from the
     enum typedef enum { preorder, postorder, endorder, leaf } VISIT; specify-
     ing 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).

     The tfind(), tsearch(), and tdelete() functions return NULL if rootp is
     NULL or the datum cannot be found.

     The twalk() function returns no value.


SEE ALSO

     bsearch(3), hsearch(3), lsearch(3)

DragonFly 3.5                    June 15, 1997                   DragonFly 3.5

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