HP 3000 Manuals HP 3000 Manuals
hsearch
Returns a pointer into a hash table, indicating the location of a
specified entry.
Syntax
#include <search.h>
ENTRY *hsearch (ENTRY item, ACTION action);
Parameters
item A structure of type ENTRY, defined in the <search.h> header
file. The item parameter contains two pointers:
* item.key points to the comparison key.
* 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.
action A member of an enumeration type ACTION which indicates the
disposition 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.
Return Values
x A pointer to an object of type ENTRY, giving the location
of the item in the table.
NULL The table is full, or the item was not found.
Description
The hsearch function returns a pointer into a hash table, indicating the
location at which a specified entry can be found. This function uses
malloc() to allocate space.
Only one hash search table may be active at any given time. The hcreate
function must be called before hsearch() to allocate sufficient space for
the hash table.
The hsearch function is a hash-table search function generalized from
Knuth Algorithm D (6.4) described in The Art of Computer Programming,
Vol.3 (Sorting and Searching) by Donald Ervin Knuth (Reading,
Mass.:Addison- Wesley, 1973).
NOTE The hsearch function and the header file <search.h> are not part of
ANSI C. Using them may make your program less portable.
Example
Refer to the example located in the hcreate function description.
See Also
hcreate(), hdestroy()