ultrix man page for hsearch

hsearch(3)						     Library Functions Manual							hsearch(3)

Name
       hsearch, hcreate, hdestroy - manage hash search tables

Syntax
       #include <search.h>

       ENTRY *hsearch (item, action)
       ENTRY item;
       ACTION action;

       int hcreate (nel)
       unsigned nel;

       void hdestroy ( )

Description
       The  subroutine is a hash-table search routine generalized from Knuth (6.4) Algorithm D.  It returns a pointer into a hash table indicating
       the location at which an entry can be found.  The item is a structure of type ENTRY (defined in the <search.h> header file) containing  two
       pointers: item.key points to the comparison key, and item.data points to any other data to be associated with that key.	(Pointers to types
       other than character should be cast to pointer-to-character.)  The action is a member of an enumeration type ACTION indicating the disposi-
       tion  of  the  entry  if  it cannot be found in the table.  ENTER indicates that the item should be inserted in the table at an appropriate
       point.  FIND indicates that no entry should be made.  Unsuccessful resolution is indicated by the return of a NULL pointer.

       The subroutine allocates sufficient space for the table, and must be called before is used.  The nel is an estimate of the  maximum  number
       of  entries  that  the  table  will contain.  This number may be adjusted upward by the algorithm in order to obtain certain mathematically
       favorable circumstances.

       The subroutine destroys the search table, and may be followed by another call to

Restrictions
       Only one hash search table may be active at any given time.

Diagnostics
       The subroutine returns a NULL pointer if either the action is FIND and the item could not be found or the action is ENTER and the table	is
       full.

       The subroutine returns zero if it cannot allocate sufficient space for the table.

See Also
       bsearch(3), lsearch(3), string(3), tsearch(3)

																	hsearch(3)