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
|
<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE cref SYSTEM "cref.dtd">
<cref>
<header>
<copyright>
<year>1996</year><year>2016</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
</legalnotice>
<title>erl_malloc</title>
<prepared>Torbjörn Törnkvist</prepared>
<responsible>Torbjörn Törnkvist</responsible>
<docno></docno>
<approved>Bjarne Däcker</approved>
<checked>Torbjörn Törnkvist</checked>
<date>980703</date>
<rev>A</rev>
<file>erl_malloc.xml</file>
</header>
<lib>erl_malloc</lib>
<libsummary>Memory Allocation Functions</libsummary>
<description>
<p>This module provides functions for allocating and deallocating
memory.</p>
</description>
<funcs>
<func>
<name><ret>ETERM *</ret><nametext>erl_alloc_eterm(etype)</nametext></name>
<fsummary>Allocates an ETERM structure.</fsummary>
<type>
<v>unsigned char etype;</v>
</type>
<desc>
<p>This function allocates an <c><![CDATA[(ETERM)]]></c> structure.
Specify <c><![CDATA[etype]]></c> as one of the following constants:</p>
<list type="bulleted">
<item>
<p>ERL_INTEGER</p>
</item>
<item>
<p>ERL_U_INTEGER <c><![CDATA[/* unsigned integer */]]></c></p>
</item>
<item>
<p>ERL_ATOM</p>
</item>
<item>
<p>ERL_PID <c><![CDATA[/* Erlang process identifier */]]></c></p>
</item>
<item>
<p>ERL_PORT</p>
</item>
<item>
<p>ERL_REF <c><![CDATA[/* Erlang reference */]]></c></p>
</item>
<item>
<p>ERL_LIST</p>
</item>
<item>
<p>ERL_EMPTY_LIST</p>
</item>
<item>
<p>ERL_TUPLE</p>
</item>
<item>
<p>ERL_BINARY</p>
</item>
<item>
<p>ERL_FLOAT</p>
</item>
<item>
<p>ERL_VARIABLE</p>
</item>
<item>
<p>ERL_SMALL_BIG <c><![CDATA[/* bignum */]]></c></p>
</item>
<item>
<p>ERL_U_SMALL_BIG <c><![CDATA[/* bignum */]]></c></p>
</item>
</list>
<p><c><![CDATA[ERL_SMALL_BIG]]></c> and <c><![CDATA[ERL_U_SMALL_BIG]]></c> are for
creating Erlang <c><![CDATA[bignums]]></c>, which can contain integers of
arbitrary size. The size of an integer in Erlang is machine
dependent, but in general any integer larger than 2^28
requires a bignum.</p>
</desc>
</func>
<func>
<name><ret>void</ret><nametext>erl_eterm_release(void)</nametext></name>
<fsummary>Clears the ETERM freelist.</fsummary>
<desc>
<p>Clears the
freelist, where blocks are placed when they are
released by <c><![CDATA[erl_free_term()]]></c> and
<c><![CDATA[erl_free_compound()]]></c>. </p>
</desc>
</func>
<func>
<name><ret>void</ret><nametext>erl_eterm_statistics(allocated, freed)</nametext></name>
<fsummary>Reports term allocation statistics.</fsummary>
<type>
<v>long *allocated;</v>
<v>long *freed;</v>
</type>
<desc>
<p><c><![CDATA[allocated]]></c> and <c><![CDATA[freed]]></c> are initialized to
contain information about the fix-allocator used to allocate
ETERM components. <c><![CDATA[allocated]]></c> is the number of blocks
currently allocated to ETERM objects. <c><![CDATA[freed]]></c> is the
length of the freelist, where blocks are placed when they are
released by <c><![CDATA[erl_free_term()]]></c> and
<c><![CDATA[erl_free_compound()]]></c>. </p>
</desc>
</func>
<func>
<name><ret>void</ret><nametext>erl_free(ptr)</nametext></name>
<fsummary>Frees some memory.</fsummary>
<type>
<v>void *ptr;</v>
</type>
<desc>
<p>This function calls the standard
<c><![CDATA[free()]]></c> function. </p>
</desc>
</func>
<func>
<name><ret>void</ret><nametext>erl_free_array(array, size)</nametext></name>
<fsummary>Frees an array of ETERM structures.</fsummary>
<type>
<v>ETERM **array;</v>
<v>int size;</v>
</type>
<desc>
<p>This function frees an array of Erlang terms.</p>
<p><c><![CDATA[array]]></c> is an array of ETERM* objects.
</p>
<p><c><![CDATA[size]]></c> is the number of terms in the array.</p>
</desc>
</func>
<func>
<name><ret>void</ret><nametext>erl_free_compound(t)</nametext></name>
<fsummary>Frees an array of ETERM structures.</fsummary>
<type>
<v>ETERM *t;</v>
</type>
<desc>
<p>Normally it is the programmer's responsibility to free each
Erlang term that has been returned from any of the
<c><![CDATA[erl_interface]]></c> functions. However since many of the
functions that build new Erlang terms in fact share objects
with other existing terms, it may be difficult for the
programmer to maintain pointers to all such terms in order to
free them individually.
</p>
<p><c><![CDATA[erl_free_compound()]]></c> will recursively free all of the
sub-terms associated with a given Erlang term, regardless of
whether we are still holding pointers to the sub-terms.
</p>
<p>There is an example in the User Manual under "Building
Terms and Patterns"
</p>
</desc>
</func>
<func>
<name><ret>void</ret><nametext>erl_free_term(t)</nametext></name>
<fsummary>Frees an ETERM structure.</fsummary>
<type>
<v>ETERM *t;</v>
</type>
<desc>
<p>Use this function to free an Erlang term.</p>
</desc>
</func>
<func>
<name><ret>void</ret><nametext>erl_malloc(size)</nametext></name>
<fsummary>Allocates some memory.</fsummary>
<type>
<v>long size;</v>
</type>
<desc>
<p>This function calls the standard
<c><![CDATA[malloc()]]></c> function. </p>
</desc>
</func>
</funcs>
</cref>
|
