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CK_RHS_INIT(3)           BSD Library Functions Manual           CK_RHS_INIT(3)

NAME
     ck_rhs_init -- initialize a hash set

LIBRARY
     Concurrency Kit (libck, -lck)

SYNOPSIS
     #include <ck_rhs.h>

     typedef unsigned long
     ck_rhs_hash_cb_t(const void *key, unsigned long seed);

     typedef bool
     ck_rhs_compare_cb_t(const void *c1, const void *c2);

     bool
     ck_rhs_init(ck_rhs_t *hs, unsigned int mode,
         ck_rhs_hash_cb_t *hash_function, ck_rhs_compare_cb_t *compare,
         struct ck_malloc *allocator, unsigned long capacity,
         unsigned long seed);

DESCRIPTION
     The ck_rhs_init() function initializes the hash set pointed to by the hs
     pointer.

     The argument mode specifies the type of key-value pairs to be stored in
     the hash set as well as the expected concurrent access model.  The value
     of mode consists of a bitfield of one of the following:

     CK_RHS_MODE_OBJECT
             The hash set is meant to store pointers to objects. This provides
             a hint that only CK_MD_VMA_BITS are necessary to encode the key
             argument. Any unused pointer bits are leveraged for internal
             optimizations.

     CK_RHS_MODE_DIRECT
             The hash set is meant to directly store key values and that all
             bits of the key are used to encode values.

     CK_RHS_MODE_READ_MOSTLY
             Optimize read operations over put/delete.

     The concurrent access model is specified by:

     CK_RHS_MODE_SPMC
             The hash set should allow for concurrent readers in the presence
             of a single writer.

     CK_RHS_MODE_MPMC
             The hash set should allow for concurrent readers in the presence
             of concurrent writers. This is currently unsupported.

     The developer is free to specify additional workload hints.  These hints
     are one of:

The argument hash_function is a mandatory pointer to a user-specified hash
function.  A user-specified hash function takes two arguments. The key argu-
ment is a pointer to a key. The seed argument is the initial seed associated
with the hash set.  This initial seed is specified by the user in
ck_rhs_init(3).

The compare argument is an optional pointer to a user-specified key comparison
function. If NULL is specified in this argument, then pointer equality will be
used to determine key equality. A user-specified comparison function takes two
arguments representing pointers to the objects being compared for equality. It
is expected to return true if the keys are of equal value and false otherwise.

The allocator argument is a pointer to a structure containing malloc and free
function pointers which respectively define the memory allocation and destruc-
tion functions to be used by the hash set being initialized.

The argument capacity represents the initial number of keys the hash set is
expected to contain. This argument is simply a hint and the underlying imple-
mentation is free to allocate more or less memory than necessary to contain
the number of entries capacity specifies.

The argument seed specifies the initial seed used by the underlying hash func-
tion.  The user is free to choose a value of their choice.

RETURN VALUES
     Upon successful completion ck_rhs_init() returns a value of true and oth-
     erwise returns a value of false to indicate an error.

ERRORS
     The behavior of ck_rhs_init() is undefined if hs is not a pointer to a
     ck_rhs_t object.

SEE ALSO
     ck_rhs_move(3), ck_rhs_destroy(3), CK_RHS_HASH(3),
     ck_rhs_iterator_init(3), ck_rhs_next(3), ck_rhs_get(3), ck_rhs_put(3),
     ck_rhs_put_unique(3), ck_rhs_set(3), ck_rhs_fas(3), ck_rhs_remove(3),
     ck_rhs_grow(3), ck_rhs_rebuild(3), ck_rhs_gc(3), ck_rhs_count(3),
     ck_rhs_reset(3), ck_rhs_reset_size(3), ck_rhs_stat(3)

     Additional information available at http://concurrencykit.org/

                              September 17, 2012