1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<link rel="stylesheet" href="style.css" type="text/css">
<meta content="text/html; charset=iso-8859-1" http-equiv="Content-Type">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="Start" href="index.html">
<link rel="previous" href="Stdlib.Unit.html">
<link rel="Up" href="Stdlib.html">
<link title="Index of types" rel=Appendix href="index_types.html">
<link title="Index of extensions" rel=Appendix href="index_extensions.html">
<link title="Index of exceptions" rel=Appendix href="index_exceptions.html">
<link title="Index of values" rel=Appendix href="index_values.html">
<link title="Index of modules" rel=Appendix href="index_modules.html">
<link title="Index of module types" rel=Appendix href="index_module_types.html">
<link title="Arg" rel="Chapter" href="Arg.html">
<link title="Array" rel="Chapter" href="Array.html">
<link title="ArrayLabels" rel="Chapter" href="ArrayLabels.html">
<link title="Bigarray" rel="Chapter" href="Bigarray.html">
<link title="Bool" rel="Chapter" href="Bool.html">
<link title="Buffer" rel="Chapter" href="Buffer.html">
<link title="Bytes" rel="Chapter" href="Bytes.html">
<link title="BytesLabels" rel="Chapter" href="BytesLabels.html">
<link title="Callback" rel="Chapter" href="Callback.html">
<link title="CamlinternalFormat" rel="Chapter" href="CamlinternalFormat.html">
<link title="CamlinternalFormatBasics" rel="Chapter" href="CamlinternalFormatBasics.html">
<link title="CamlinternalLazy" rel="Chapter" href="CamlinternalLazy.html">
<link title="CamlinternalMod" rel="Chapter" href="CamlinternalMod.html">
<link title="CamlinternalOO" rel="Chapter" href="CamlinternalOO.html">
<link title="Char" rel="Chapter" href="Char.html">
<link title="Complex" rel="Chapter" href="Complex.html">
<link title="Condition" rel="Chapter" href="Condition.html">
<link title="Digest" rel="Chapter" href="Digest.html">
<link title="Dynlink" rel="Chapter" href="Dynlink.html">
<link title="Ephemeron" rel="Chapter" href="Ephemeron.html">
<link title="Event" rel="Chapter" href="Event.html">
<link title="Filename" rel="Chapter" href="Filename.html">
<link title="Float" rel="Chapter" href="Float.html">
<link title="Format" rel="Chapter" href="Format.html">
<link title="Fun" rel="Chapter" href="Fun.html">
<link title="Gc" rel="Chapter" href="Gc.html">
<link title="Genlex" rel="Chapter" href="Genlex.html">
<link title="Hashtbl" rel="Chapter" href="Hashtbl.html">
<link title="Int" rel="Chapter" href="Int.html">
<link title="Int32" rel="Chapter" href="Int32.html">
<link title="Int64" rel="Chapter" href="Int64.html">
<link title="Lazy" rel="Chapter" href="Lazy.html">
<link title="Lexing" rel="Chapter" href="Lexing.html">
<link title="List" rel="Chapter" href="List.html">
<link title="ListLabels" rel="Chapter" href="ListLabels.html">
<link title="Map" rel="Chapter" href="Map.html">
<link title="Marshal" rel="Chapter" href="Marshal.html">
<link title="MoreLabels" rel="Chapter" href="MoreLabels.html">
<link title="Mutex" rel="Chapter" href="Mutex.html">
<link title="Nativeint" rel="Chapter" href="Nativeint.html">
<link title="Obj" rel="Chapter" href="Obj.html">
<link title="Ocaml_operators" rel="Chapter" href="Ocaml_operators.html">
<link title="Oo" rel="Chapter" href="Oo.html">
<link title="Option" rel="Chapter" href="Option.html">
<link title="Parsing" rel="Chapter" href="Parsing.html">
<link title="Printexc" rel="Chapter" href="Printexc.html">
<link title="Printf" rel="Chapter" href="Printf.html">
<link title="Queue" rel="Chapter" href="Queue.html">
<link title="Random" rel="Chapter" href="Random.html">
<link title="Result" rel="Chapter" href="Result.html">
<link title="Scanf" rel="Chapter" href="Scanf.html">
<link title="Seq" rel="Chapter" href="Seq.html">
<link title="Set" rel="Chapter" href="Set.html">
<link title="Spacetime" rel="Chapter" href="Spacetime.html">
<link title="Stack" rel="Chapter" href="Stack.html">
<link title="StdLabels" rel="Chapter" href="StdLabels.html">
<link title="Stdlib" rel="Chapter" href="Stdlib.html">
<link title="Str" rel="Chapter" href="Str.html">
<link title="Stream" rel="Chapter" href="Stream.html">
<link title="String" rel="Chapter" href="String.html">
<link title="StringLabels" rel="Chapter" href="StringLabels.html">
<link title="Sys" rel="Chapter" href="Sys.html">
<link title="Thread" rel="Chapter" href="Thread.html">
<link title="ThreadUnix" rel="Chapter" href="ThreadUnix.html">
<link title="Uchar" rel="Chapter" href="Uchar.html">
<link title="Unit" rel="Chapter" href="Unit.html">
<link title="Unix" rel="Chapter" href="Unix.html">
<link title="UnixLabels" rel="Chapter" href="UnixLabels.html">
<link title="Weak" rel="Chapter" href="Weak.html"><link title="Low-level functions" rel="Section" href="#1_Lowlevelfunctions">
<link title="Weak hash sets" rel="Section" href="#1_Weakhashsets">
<title>Stdlib.Weak</title>
</head>
<body>
<div class="navbar"><a class="pre" href="Stdlib.Unit.html" title="Stdlib.Unit">Previous</a>
<a class="up" href="Stdlib.html" title="Stdlib">Up</a>
</div>
<h1>Module <a href="type_Stdlib.Weak.html">Stdlib.Weak</a></h1>
<pre><span id="MODULEWeak"><span class="keyword">module</span> Weak</span>: <code class="type"><a href="Weak.html">Weak</a></code></pre><hr width="100%">
<h2 id="1_Lowlevelfunctions">Low-level functions</h2>
<pre><span id="TYPEt"><span class="keyword">type</span> <code class="type">'a</code> t</span> </pre>
<div class="info ">
<div class="info-desc">
<p>The type of arrays of weak pointers (weak arrays). A weak
pointer is a value that the garbage collector may erase whenever
the value is not used any more (through normal pointers) by the
program. Note that finalisation functions are run before the
weak pointers are erased, because the finalisation functions
can make values alive again (before 4.03 the finalisation
functions were run after).</p>
<p>A weak pointer is said to be full if it points to a value,
empty if the value was erased by the GC.</p>
<p>Notes:</p>
<ul>
<li>Integers are not allocated and cannot be stored in weak arrays.</li>
<li>Weak arrays cannot be marshaled using <a href="Stdlib.html#VALoutput_value"><code class="code">output_value</code></a>
nor the functions of the <a href="Marshal.html"><code class="code"><span class="constructor">Marshal</span></code></a> module.</li>
</ul>
</div>
</div>
<pre><span id="VALcreate"><span class="keyword">val</span> create</span> : <code class="type">int -> 'a <a href="Weak.html#TYPEt">t</a></code></pre><div class="info ">
<div class="info-desc">
<p><code class="code"><span class="constructor">Weak</span>.create n</code> returns a new weak array of length <code class="code">n</code>.
All the pointers are initially empty.</p>
</div>
<ul class="info-attributes">
<li><b>Raises</b> <code>Invalid_argument</code> if <code class="code">n</code> is not comprised between zero and
<a href="Obj.Ephemeron.html#VALmax_ephe_length"><code class="code"><span class="constructor">Obj</span>.<span class="constructor">Ephemeron</span>.max_ephe_length</code></a> (limits included).</li>
</ul>
</div>
<pre><span id="VALlength"><span class="keyword">val</span> length</span> : <code class="type">'a <a href="Weak.html#TYPEt">t</a> -> int</code></pre><div class="info ">
<div class="info-desc">
<p><code class="code"><span class="constructor">Weak</span>.length ar</code> returns the length (number of elements) of
<code class="code">ar</code>.</p>
</div>
</div>
<pre><span id="VALset"><span class="keyword">val</span> set</span> : <code class="type">'a <a href="Weak.html#TYPEt">t</a> -> int -> 'a option -> unit</code></pre><div class="info ">
<div class="info-desc">
<p><code class="code"><span class="constructor">Weak</span>.set ar n (<span class="constructor">Some</span> el)</code> sets the <code class="code">n</code>th cell of <code class="code">ar</code> to be a
(full) pointer to <code class="code">el</code>; <code class="code"><span class="constructor">Weak</span>.set ar n <span class="constructor">None</span></code> sets the <code class="code">n</code>th
cell of <code class="code">ar</code> to empty.</p>
</div>
<ul class="info-attributes">
<li><b>Raises</b> <code>Invalid_argument</code> if <code class="code">n</code> is not in the range
0 to <a href="Weak.html#VALlength"><code class="code"><span class="constructor">Weak</span>.length</code></a><code class="code"> a - 1</code>.</li>
</ul>
</div>
<pre><span id="VALget"><span class="keyword">val</span> get</span> : <code class="type">'a <a href="Weak.html#TYPEt">t</a> -> int -> 'a option</code></pre><div class="info ">
<div class="info-desc">
<p><code class="code"><span class="constructor">Weak</span>.get ar n</code> returns None if the <code class="code">n</code>th cell of <code class="code">ar</code> is
empty, <code class="code"><span class="constructor">Some</span> x</code> (where <code class="code">x</code> is the value) if it is full.</p>
</div>
<ul class="info-attributes">
<li><b>Raises</b> <code>Invalid_argument</code> if <code class="code">n</code> is not in the range
0 to <a href="Weak.html#VALlength"><code class="code"><span class="constructor">Weak</span>.length</code></a><code class="code"> a - 1</code>.</li>
</ul>
</div>
<pre><span id="VALget_copy"><span class="keyword">val</span> get_copy</span> : <code class="type">'a <a href="Weak.html#TYPEt">t</a> -> int -> 'a option</code></pre><div class="info ">
<div class="info-desc">
<p><code class="code"><span class="constructor">Weak</span>.get_copy ar n</code> returns None if the <code class="code">n</code>th cell of <code class="code">ar</code> is
empty, <code class="code"><span class="constructor">Some</span> x</code> (where <code class="code">x</code> is a (shallow) copy of the value) if
it is full.
In addition to pitfalls with mutable values, the interesting
difference with <code class="code">get</code> is that <code class="code">get_copy</code> does not prevent
the incremental GC from erasing the value in its current cycle
(<code class="code">get</code> may delay the erasure to the next GC cycle).</p>
</div>
<ul class="info-attributes">
<li><b>Raises</b> <code>Invalid_argument</code> if <code class="code">n</code> is not in the range
0 to <a href="Weak.html#VALlength"><code class="code"><span class="constructor">Weak</span>.length</code></a><code class="code"> a - 1</code>.
If the element is a custom block it is not copied.</li>
</ul>
</div>
<pre><span id="VALcheck"><span class="keyword">val</span> check</span> : <code class="type">'a <a href="Weak.html#TYPEt">t</a> -> int -> bool</code></pre><div class="info ">
<div class="info-desc">
<p><code class="code"><span class="constructor">Weak</span>.check ar n</code> returns <code class="code"><span class="keyword">true</span></code> if the <code class="code">n</code>th cell of <code class="code">ar</code> is
full, <code class="code"><span class="keyword">false</span></code> if it is empty. Note that even if <code class="code"><span class="constructor">Weak</span>.check ar n</code>
returns <code class="code"><span class="keyword">true</span></code>, a subsequent <a href="Weak.html#VALget"><code class="code"><span class="constructor">Weak</span>.get</code></a><code class="code"> ar n</code> can return <code class="code"><span class="constructor">None</span></code>.</p>
</div>
</div>
<pre><span id="VALfill"><span class="keyword">val</span> fill</span> : <code class="type">'a <a href="Weak.html#TYPEt">t</a> -> int -> int -> 'a option -> unit</code></pre><div class="info ">
<div class="info-desc">
<p><code class="code"><span class="constructor">Weak</span>.fill ar ofs len el</code> sets to <code class="code">el</code> all pointers of <code class="code">ar</code> from
<code class="code">ofs</code> to <code class="code">ofs + len - 1</code>.</p>
</div>
<ul class="info-attributes">
<li><b>Raises</b> <code>Invalid_argument</code> if <code class="code">ofs</code> and <code class="code">len</code> do not designate a valid subarray of <code class="code">a</code>.</li>
</ul>
</div>
<pre><span id="VALblit"><span class="keyword">val</span> blit</span> : <code class="type">'a <a href="Weak.html#TYPEt">t</a> -> int -> 'a <a href="Weak.html#TYPEt">t</a> -> int -> int -> unit</code></pre><div class="info ">
<div class="info-desc">
<p><code class="code"><span class="constructor">Weak</span>.blit ar1 off1 ar2 off2 len</code> copies <code class="code">len</code> weak pointers
from <code class="code">ar1</code> (starting at <code class="code">off1</code>) to <code class="code">ar2</code> (starting at <code class="code">off2</code>).
It works correctly even if <code class="code">ar1</code> and <code class="code">ar2</code> are the same.</p>
</div>
<ul class="info-attributes">
<li><b>Raises</b> <code>Invalid_argument</code> if <code class="code">off1</code> and <code class="code">len</code> do
not designate a valid subarray of <code class="code">ar1</code>, or if <code class="code">off2</code> and <code class="code">len</code>
do not designate a valid subarray of <code class="code">ar2</code>.</li>
</ul>
</div>
<h2 id="1_Weakhashsets">Weak hash sets</h2><p>A weak hash set is a hashed set of values. Each value may
magically disappear from the set when it is not used by the
rest of the program any more. This is normally used to share
data structures without inducing memory leaks.
Weak hash sets are defined on values from a <a href="Hashtbl.HashedType.html"><code class="code"><span class="constructor">Hashtbl</span>.<span class="constructor">HashedType</span></code></a>
module; the <code class="code">equal</code> relation and <code class="code">hash</code> function are taken from that
module. We will say that <code class="code">v</code> is an instance of <code class="code">x</code> if <code class="code">equal x v</code>
is <code class="code"><span class="keyword">true</span></code>.</p>
<p>The <code class="code">equal</code> relation must be able to work on a shallow copy of
the values and give the same result as with the values themselves.</p>
<pre><span id="MODULETYPES"><span class="keyword">module type</span> <a href="Weak.S.html">S</a></span> = <code class="code"><span class="keyword">sig</span></code> <a href="Weak.S.html">..</a> <code class="code"><span class="keyword">end</span></code></pre><div class="info">
<p>The output signature of the functor <a href="Weak.Make.html"><code class="code"><span class="constructor">Weak</span>.<span class="constructor">Make</span></code></a>.</p>
</div>
<pre><span id="MODULEMake"><span class="keyword">module</span> <a href="Weak.Make.html">Make</a></span>: <div class="sig_block"><code class="code"><span class="keyword">functor</span> (</code><code class="code"><span class="constructor">H</span></code><code class="code"> : </code><code class="type"><a href="Hashtbl.HashedType.html">Hashtbl.HashedType</a></code><code class="code">) <span class="keywordsign">-></span> </code><code class="type"><a href="Weak.S.html">S</a></code><code class="type"> with type data = H.t</code></div></pre><div class="info">
<p>Functor building an implementation of the weak hash set structure.</p>
</div>
</body></html>
|
