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.\" Copyright (c) 2001 Tobias Weingartner
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.Dd $Mdocdate: September 24 2016 $
.Dt HASHINIT 9
.Os
.Sh NAME
.Nm hashinit ,
.Nm hashfree
.Nd kernel hashtable functions
.Sh SYNOPSIS
.In sys/systm.h
.Ft void *
.Fn hashinit "int num" "int type" "int flags" "u_long *mask"
.Ft void
.Fn hashfree "void *hash" "int num" "int type"
.Sh DESCRIPTION
The
.Fn hashinit
function is used to allocate a hashtable of a desired size given by the
.Fa num
argument.
The
.Fn hashinit
function will round this number to the next power of two, and
allocate and initialize the requested hashtable.
The
.Fa type
and
.Fa flags
arguments are passed to the
.Xr malloc 9
function unchanged.
The
.Fa mask
argument is used to pass back the mask for use with the allocated
hashing table.
.Pp
The
.Fn hashfree
function causes memory allocated by the
.Fn hashinit
function to be released.
The
.Fa num
and
.Fa type
arguments of related calls must match.
.Sh RETURN VALUES
The
.Fn hashinit
function returns a pointer to the allocated and initialized hash table.
.Sh SEE ALSO
.Xr free 9 ,
.Xr malloc 9
.Sh LIMITATIONS
The
.Fn hashinit
function currently only allocates hash tables with LIST bucket pointers
at this time.
Future enhancements to allocate QUEUE bucket pointers may be warranted.
This may necessitate an API change to accommodate.
.Sh HISTORY
The
.Nm
function first appeared in
.Bx 4.4 .