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
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
|
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
<refentry>
<refentryinfo>
<keywordset>
<keyword>clEnqueueMapBuffer</keyword>
</keywordset>
</refentryinfo>
<refmeta>
<refentrytitle>
clEnqueueMapBuffer
</refentrytitle>
<refmiscinfo>
<copyright>
<year>2007-2011</year>
<holder>The Khronos Group Inc.
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and/or associated documentation files (the
"Materials"), to deal in the Materials without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Materials, and to
permit persons to whom the Materials are furnished to do so, subject to
the condition that this copyright notice and permission notice shall be included
in all copies or substantial portions of the Materials.</holder>
</copyright>
</refmiscinfo>
<manvolnum>3</manvolnum>
</refmeta>
<!-- ================================ SYNOPSIS -->
<refnamediv id="clEnqueueMapBuffer">
<refname>
clEnqueueMapBuffer
</refname>
<refpurpose>
Enqueues a command to map a region of the buffer object given by <varname>buffer</varname>
into the host address space and returns a pointer to this mapped region.
</refpurpose>
</refnamediv>
<refsynopsisdiv xmlns:xlink="http://www.w3.org/1999/xlink"><title></title>
<funcsynopsis>
<funcprototype>
<funcdef>
<link xlink:href="scalarDataTypes.html">void</link> * <function>clEnqueueMapBuffer</function>
</funcdef>
<paramdef><link xlink:href="abstractDataTypes.html">cl_command_queue</link><parameter>command_queue</parameter></paramdef>
<paramdef><link xlink:href="abstractDataTypes.html">cl_mem</link><parameter>buffer</parameter></paramdef>
<paramdef><link xlink:href="enums.html#cl_bool">cl_bool</link><parameter>blocking_map</parameter></paramdef>
<paramdef><link xlink:href="enums.html#cl_map_flags">cl_map_flags</link><parameter>map_flags</parameter></paramdef>
<paramdef><link xlink:href="scalarDataTypes.html">size_t</link><parameter>offset</parameter></paramdef>
<paramdef><link xlink:href="scalarDataTypes.html">size_t</link><parameter>size</parameter></paramdef>
<paramdef><link xlink:href="scalarDataTypes.html">cl_uint</link><parameter>num_events_in_wait_list</parameter></paramdef>
<paramdef>const <link xlink:href="abstractDataTypes.html">cl_event</link><parameter>*event_wait_list</parameter></paramdef>
<paramdef><link xlink:href="abstractDataTypes.html">cl_event</link><parameter>*event</parameter></paramdef>
<paramdef><link xlink:href="scalarDataTypes.html">cl_int</link><parameter>*errcode_ret</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<!-- ================================ PARAMETERS -->
<refsect1 id="parameters">
<title>Parameters</title>
<variablelist>
<varlistentry>
<term> <varname> command_queue </varname> </term>
<listitem>
<para>
Must be a valid command-queue.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term> <varname> blocking_map </varname> </term>
<listitem>
<para>
Indicates if the map operation is <varname>blocking</varname> or
<varname>non-blocking</varname>.
</para>
<para>
If <varname>blocking_map</varname> is <constant>CL_TRUE</constant>,
<function>clEnqueueMapBuffer</function> does not return until the specified
region in <varname>buffer</varname> is mapped into the host address space
and the application can access the contents of the mapped region using
the pointer returned by <function>clEnqueueMapBuffer</function>.
</para>
<para>
If <varname>blocking_map</varname> is <constant>CL_FALSE</constant>
i.e. map operation is non-blocking, the pointer to the mapped region
returned by <function>clEnqueueMapBuffer</function> cannot be used until
the map command has completed. The <varname>event</varname> argument
returns an event object which can be used to query the execution status
of the map command. When the map command is completed, the application
can access the contents of the mapped region using the pointer returned
by <function>clEnqueueMapBuffer</function>.
</para>
</listitem>
</varlistentry>
<!-- ================================ PARAMETER TABLE (OPTIONAL) -->
<!-- DELETE IF NOT NEEDED -->
<!-- Use this if parameter information requires a table. Adjust the number of columns by adjusting
<colspec /> tags. Column header goes in the <thead /> section. Delte the section if no column head needed.
-->
<varlistentry>
<term><varname>map_flags</varname></term>
<listitem>
<para>
A bit-bield with the following supported values.
</para>
<!-- table 5.5, also applies to clEnqueueMapImage.xml -->
<informaltable frame="all"><tgroup cols="2" align="left" colsep="1" rowsep="1">
<colspec colname="col1" colnum="1" />
<colspec colname="col2" colnum="2" />
<thead>
<row>
<entry>cl_map_flags</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry><constant>CL_MAP_READ</constant></entry>
<entry>
<para>
This flag specifies that the region being mapped in the memory
object is being mapped for reading.
</para>
<para>
The pointer returned by <function>clEnqueueMapBuffer</function> or
<citerefentry><refentrytitle>clEnqueueMapImage</refentrytitle></citerefentry>
is guaranteed to contain
the latest bits in the region being
mapped when the <function>clEnqueueMapBuffer</function> or
<citerefentry><refentrytitle>clEnqueueMapImage</refentrytitle></citerefentry>
command has completed.
</para>
</entry>
</row>
<row>
<entry><constant>CL_MAP_WRITE</constant></entry>
<entry>
<para>
This flag specifies that the region being mapped in the memory
object is being mapped for writing.
</para>
<para>
The pointer returned by <function>clEnqueueMapBuffer</function> or
<citerefentry><refentrytitle>clEnqueueMapImage</refentrytitle></citerefentry>
is guaranteed to contain the latest bits in
the region being mapped when the <function>clEnqueueMapBuffer</function> or
<citerefentry><refentrytitle>clEnqueueMapImage</refentrytitle></citerefentry>
command has completed.
</para>
</entry>
</row>
<row>
<entry><constant>CL_MAP_WRITE_INVALIDATE_REGION</constant></entry>
<entry>
<para>
This flag specifies that the region being mapped in the memory
object is being mapped for writing.
</para>
<para>
The contents of the region being mapped are to be discarded.
This is typically the case
when the region being mapped is overwritten by the host. This
flag allows the implementation
to no longer guarantee that the pointer returned by
<function>clEnqueueMapBuffer</function> or
<citerefentry><refentrytitle>clEnqueueMapImage</refentrytitle></citerefentry>
contains the latest bits in the region being
mapped which can be a significant performance enhancement.
</para>
<para>
<constant>CL_MAP_READ</constant> or <constant>CL_MAP_WRITE</constant>
and <constant> CL_MAP_WRITE_INVALIDATE_REGION</constant>
are mutually exclusive.
</para>
</entry>
</row>
</tbody>
</tgroup></informaltable>
</listitem>
</varlistentry>
<!-- ================================ END PARAMETER TABLE -->
<varlistentry>
<term> <varname> buffer </varname> </term>
<listitem>
<para>
A valid buffer object. The OpenCL context associated with <varname>command_queue</varname>
and <varname>buffer</varname> must be the same.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<varname>
offset,
</varname>
<varname>
size
</varname>
</term>
<listitem>
<para>
The offset in bytes and the size of the region in the buffer object that is being mapped.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<varname>
event_wait_list,
</varname>
<varname>
num_events_in_wait_list
</varname>
</term>
<listitem>
<para>
Specify events that need to complete before this particular
command can be executed. If <varname>event_wait_list</varname>
is NULL, then this particular command does not wait on any
event to complete. If <varname>event_wait_list</varname> is
NULL, <varname>num_events_in_wait_list</varname> must be 0. If
<varname>event_wait_list</varname> is not NULL, the list of events
pointed to by <varname>event_wait_list</varname> must be valid
and <varname>num_events_in_wait_list</varname> must be greater
than 0. The events specified in <varname>event_wait_list</varname>
act as synchronization points. The context associated with events in
<varname>event_wait_list</varname> and <varname>command_queue</varname> must
be the same. The memory associated with <varname>event_wait_list</varname>
can be reused or freed after the function returns.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term> <varname> event </varname> </term>
<listitem>
<para>
Returns an event object that identifies this particular copy command
and can be used to query or queue a wait for this particular command
to complete. <varname>event</varname> can be NULL in which case
it will not be possible for the application to query the status of
this command or queue a wait for this command to complete. If the
<varname>event_wait_list</varname> and the <varname>event</varname>
arguments are not NULL, the <varname>event</varname> argument should not
refer to an element of the <varname>event_wait_list</varname> array.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term> <varname> errcode_ret </varname> </term>
<listitem>
<para>
Returns an appropriate error code. If <varname>errcode_ret</varname>
is NULL, no error code is returned.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<!-- ================================ NOTES -->
<refsect1 id="notes"><title>Notes</title>
<para>
The returned pointer maps a region starting at <varname>offset</varname> and is at
least <varname>size</varname> bytes in size. The result of a memory access outside
this region is undefined.
</para>
<para>
If the buffer object is created with <constant>CL_MEM_USE_HOST_PTR</constant> set in
<varname>mem_flags</varname>, the following will be true:
</para>
<itemizedlist mark="disc">
<listitem>
The <varname>host_ptr</varname> specified in
<citerefentry><refentrytitle>clCreateBuffer</refentrytitle></citerefentry>
is guaranteed to contain the latest bits in the region being mapped when the
<function>clEnqueueMapBuffer</function> command has completed.
</listitem>
<listitem>
The pointer value returned by <function>clEnqueueMapBuffer</function> will be derived
from the <varname>host_ptr</varname> specified when the buffer object is created.
</listitem>
</itemizedlist>
<para>
Mapped buffer objects are unmapped using
<citerefentry><refentrytitle>clEnqueueUnmapMemObject</refentrytitle></citerefentry>.
</para>
<para>
<!-- core spec p. 120, section 5.4.2 --> <function>clEnqueueMapBuffer</function>
and <citerefentry><refentrytitle>clEnqueueMapImage</refentrytitle></citerefentry>
increment the mapped count of the memory object. The initial mapped count value of a
memory object is zero. Multiple calls to <function>clEnqueueMapBuffer</function> or
<citerefentry><refentrytitle>clEnqueueMapImage</refentrytitle></citerefentry> on the
same memory object will increment this mapped count by appropriate number of calls.
<citerefentry><refentrytitle>clEnqueueUnmapMemObject</refentrytitle></citerefentry>
decrements the mapped count of the memory object.
</para>
<para>
<!-- core spec p. 120, section 5.4.2 --> <function>clEnqueueMapBuffer</function>
and <citerefentry><refentrytitle>clEnqueueMapImage</refentrytitle></citerefentry>
act as synchronization points for a region of the buffer object being mapped.
</para>
</refsect1>
<!-- ================================ ERRORS -->
<refsect1 id="errors"><title>Errors</title>
<para>
<function>clEnqueueMapBuffer</function> will return a pointer to the mapped region
if the function is executed successfully. The <varname>errcode_ret</varname> is set
to <errorname>CL_SUCCESS</errorname>.
</para>
<para>
A NULL pointer is returned otherwise with one of the following error values returned
in <varname>errcode_ret</varname>:
</para>
<itemizedlist mark="disc">
<listitem>
<errorname>CL_INVALID_COMMAND_QUEUE</errorname> if <varname>command_queue</varname>
is not a valid command-queue.
</listitem>
<listitem>
<errorname>CL_INVALID_CONTEXT</errorname> if the context associated with
<varname>command_queue</varname> and <varname>image</varname>
are not the same or if the context associated with <varname>command_queue</varname>
and events in <varname>event_wait_list</varname> are not the same.
</listitem>
<listitem>
<errorname>CL_INVALID_MEM_OBJECT</errorname> if <varname>image</varname> is not a valid image object.
</listitem>
<listitem>
<errorname>CL_INVALID_VALUE</errorname> if region being mapped given by
(<varname>offset</varname>, <varname>size</varname>)
is out of bounds or if <varname>size</varname> is 0 or values specified in
<varname>map_flags</varname> are not valid.
</listitem>
<listitem>
<errorname>CL_INVALID_EVENT_WAIT_LIST</errorname>
if <varname>event_wait_list</varname> is NULL and
<varname>num_events_in_wait_list</varname> > 0,
or <varname>event_wait_list</varname> is not NULL and
<varname>num_events_in_wait_list</varname> is 0, or if event objects in
<varname>event_wait_list</varname> are not valid events.
</listitem>
<listitem>
<errorname>CL_MISALIGNED_SUB_BUFFER_OFFSET</errorname> if
<varname>buffer</varname> is a sub-buffer object and <varname>offset</varname>
specified when the sub-buffer object is created is not aligned to
<constant>CL_DEVICE_MEM_BASE_ADDR_ALIGN</constant> value for device associated
with <varname>queue</varname>.
</listitem>
<listitem>
<errorname>CL_MAP_FAILURE</errorname> if there is a failure to map the
requested region into the host address space. This error cannot occur for
image objects created with <constant>CL_MEM_USE_HOST_PTR</constant> or
<constant>CL_MEM_ALLOC_HOST_PTR</constant>.
</listitem>
<listitem>
<errorname>CL_EXEC_STATUS_ERROR_FOR_EVENTS_IN_WAIT_LIST</errorname> if the
map operation is blocking and the execution status of any of the events in
<varname>event_wait_list</varname> is a negative integer value.
</listitem>
<listitem>
<errorname>CL_MEM_OBJECT_ALLOCATION_FAILURE</errorname> if there is a failure to
allocate memory for data store associated with <varname>buffer</varname>.
</listitem>
<listitem>
<errorname>CL_INVALID_OPERATION</errorname> if <varname>buffer</varname>
has been created with <constant>CL_MEM_HOST_WRITE_ONLY</constant> or
<constant>CL_MEM_HOST_NO_ACCESS</constant> and <constant>CL_MAP_READ</constant>
is set in <varname>map_flags</varname> or if <varname>buffer</varname>
has been created with <constant>CL_MEM_HOST_READ_ONL</constant> or
<constant>CL_MEM_HOST_NO_ACCESS</constant> and <constant>CL_MAP_WRITE</constant>
or <constant>CL_MAP_WRITE_INVALIDATE_REGION</constant> is set in
<varname>map_flags</varname>.
</listitem>
<listitem>
<errorname>CL_OUT_OF_RESOURCES</errorname> if there is a failure to allocate
resources required by the OpenCL implementation on the device.
</listitem>
<listitem>
<errorname>CL_OUT_OF_HOST_MEMORY</errorname> if there is a failure to allocate
resources required by the OpenCL implementation on the host.
</listitem>
</itemizedlist>
</refsect1>
<!-- ================================ EXAMPLE -->
<!-- DO NOT DELETE IN CASE AN EXAMPLE IS ADDED IN THE FUTURE -->
<!--
<refsect2 id="example1">
<title>
Example
</title>
<informaltable frame="none">
<tgroup cols="1" align="left" colsep="0" rowsep="0">
<colspec colname="col1" colnum="1" />
<tbody>
<row>
<entry>
Example goes here - it will be set in "code" type with white space preserved.
</entry>
</row>
</tbody>
</tgroup>
</informaltable>
</refsect2>
-->
<!-- ================================ SPECIFICATION -->
<!-- Set the "uri" attribute in the <olink /> element to the "named destination" for the PDF page
-->
<refsect1 id="specification"><title>Specification</title>
<para>
<imageobject>
<imagedata fileref="pdficon_small1.gif" format="gif" />
</imageobject>
<olink uri="clEnqueueMapBuffer">OpenCL Specification</olink>
</para>
</refsect1>
<!-- ================================ ALSO SEE -->
<refsect1 id="seealso"><title>Also see</title>
<para>
<citerefentry><refentrytitle>clEnqueueMapImage</refentrytitle></citerefentry>,
<citerefentry><refentrytitle>clEnqueueUnmapMemObject</refentrytitle></citerefentry>
</para>
</refsect1>
<!-- ================================ COPYRIGHT -->
<!-- Content included from copyright.inc.xsl -->
<refsect3 id="Copyright"><title></title>
<imageobject>
<imagedata fileref="KhronosLogo.jpg" format="jpg" />
</imageobject>
<para />
</refsect3>
<!-- 18-Oct-2011 -->
</refentry>
|
