-
Notifications
You must be signed in to change notification settings - Fork 10
Expand file tree
/
Copy pathctypes.po
More file actions
2697 lines (2021 loc) · 107 KB
/
Copy pathctypes.po
File metadata and controls
2697 lines (2021 loc) · 107 KB
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
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
# SOME DESCRIPTIVE TITLE.
# Copyright (C) 2001 Python Software Foundation
# This file is distributed under the same license as the Python package.
# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
#
# Translators:
# Danial Behzadi <dani.behzi@ubuntu.com>, 2025
# Alireza Shabani (Revisto) <theRevisto@gmail.com>, 2025
# Rafael Fontenelle <rffontenelle@gmail.com>, 2025
# Sepehr Rasouli <sepehrrasouli06@gmail.com>, 2026
#
#, fuzzy
msgid ""
msgstr ""
"Project-Id-Version: Python 3.14\n"
"Report-Msgid-Bugs-To: \n"
"POT-Creation-Date: 2026-08-18 04:30+0000\n"
"PO-Revision-Date: 2021-06-28 01:03+0000\n"
"Last-Translator: Sepehr Rasouli <sepehrrasouli06@gmail.com>, 2026\n"
"Language-Team: Persian (https://github.com/revisto/python-docs-fa/fa/)\n"
"Language: fa\n"
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=UTF-8\n"
"Content-Transfer-Encoding: 8bit\n"
"Plural-Forms: nplurals=2; plural=(n > 1);\n"
msgid ":mod:`!ctypes` --- A foreign function library for Python"
msgstr ""
msgid "**Source code:** :source:`Lib/ctypes`"
msgstr ""
msgid ":mod:`!ctypes` is a foreign function library for Python. It provides C compatible data types, and allows calling functions in DLLs or shared libraries. It can be used to wrap these libraries in pure Python."
msgstr ""
msgid "This is an :term:`optional module`. If it is missing from your copy of CPython, look for documentation from your distributor (that is, whoever provided Python to you). If you are the distributor, see :ref:`optional-module-requirements`."
msgstr ""
msgid ":mod:`!ctypes` provides low-level access to native libraries and the process's memory, bypassing Python's safety mechanisms and allowing execution of arbitrary native code. Incorrect use can corrupt data and objects, reveal sensitive information, cause crashes, or otherwise compromise the running process."
msgstr ""
msgid "ctypes tutorial"
msgstr ""
msgid "Note: Some code samples reference the ctypes :class:`c_int` type. On platforms where ``sizeof(long) == sizeof(int)`` it is an alias to :class:`c_long`. So, you should not be confused if :class:`c_long` is printed if you would expect :class:`c_int` --- they are actually the same type."
msgstr ""
msgid "Loading dynamic link libraries"
msgstr ""
msgid ":mod:`!ctypes` exports the :py:data:`~ctypes.cdll`, and on Windows :py:data:`~ctypes.windll` and :py:data:`~ctypes.oledll` objects, for loading dynamic link libraries."
msgstr ""
msgid "You load libraries by accessing them as attributes of these objects. :py:data:`!cdll` loads libraries which export functions using the standard ``cdecl`` calling convention, while :py:data:`!windll` libraries call functions using the ``stdcall`` calling convention. :py:data:`~oledll` also uses the ``stdcall`` calling convention, and assumes the functions return a Windows :c:type:`!HRESULT` error code. The error code is used to automatically raise an :class:`OSError` exception when the function call fails."
msgstr ""
msgid "Windows errors used to raise :exc:`WindowsError`, which is now an alias of :exc:`OSError`."
msgstr ""
msgid "Here are some examples for Windows. Note that ``msvcrt`` is the MS standard C library containing most standard C functions, and uses the ``cdecl`` calling convention::"
msgstr ""
msgid ""
">>> from ctypes import *\n"
">>> print(windll.kernel32)\n"
"<WinDLL 'kernel32', handle ... at ...>\n"
">>> print(cdll.msvcrt)\n"
"<CDLL 'msvcrt', handle ... at ...>\n"
">>> libc = cdll.msvcrt\n"
">>>"
msgstr ""
msgid "Windows appends the usual ``.dll`` file suffix automatically."
msgstr ""
msgid "Accessing the standard C library through ``cdll.msvcrt`` will use an outdated version of the library that may be incompatible with the one being used by Python. Where possible, use native Python functionality, or else import and use the ``msvcrt`` module."
msgstr ""
msgid "Other systems require the filename *including* the extension to load a library, so attribute access can not be used to load libraries. Either the :meth:`~LibraryLoader.LoadLibrary` method of the dll loaders should be used, or you should load the library by creating an instance of :py:class:`CDLL` by calling the constructor."
msgstr ""
msgid "For example, on Linux::"
msgstr ""
msgid ""
">>> cdll.LoadLibrary(\"libc.so.6\")\n"
"<CDLL 'libc.so.6', handle ... at ...>\n"
">>> libc = CDLL(\"libc.so.6\")\n"
">>> libc\n"
"<CDLL 'libc.so.6', handle ... at ...>\n"
">>>"
msgstr ""
msgid "On macOS::"
msgstr ""
msgid ""
">>> cdll.LoadLibrary(\"libc.dylib\")\n"
"<CDLL 'libc.dylib', handle ... at ...>\n"
">>> libc = CDLL(\"libc.dylib\")\n"
">>> libc\n"
"<CDLL 'libc.dylib', handle ... at ...>"
msgstr ""
msgid "Accessing functions from loaded dlls"
msgstr ""
msgid "Functions are accessed as attributes of dll objects::"
msgstr ""
msgid ""
">>> libc.printf\n"
"<_FuncPtr object at 0x...>\n"
">>> print(windll.kernel32.GetModuleHandleA)\n"
"<_FuncPtr object at 0x...>\n"
">>> print(windll.kernel32.MyOwnFunction)\n"
"Traceback (most recent call last):\n"
" File \"<stdin>\", line 1, in <module>\n"
" File \"ctypes.py\", line 239, in __getattr__\n"
" func = _StdcallFuncPtr(name, self)\n"
"AttributeError: function 'MyOwnFunction' not found\n"
">>>"
msgstr ""
msgid "Note that win32 system dlls like ``kernel32`` and ``user32`` often export ANSI as well as UNICODE versions of a function. The UNICODE version is exported with a ``W`` appended to the name, while the ANSI version is exported with an ``A`` appended to the name. The win32 ``GetModuleHandle`` function, which returns a *module handle* for a given module name, has the following C prototype, and a macro is used to expose one of them as ``GetModuleHandle`` depending on whether UNICODE is defined or not::"
msgstr ""
msgid ""
"/* ANSI version */\n"
"HMODULE GetModuleHandleA(LPCSTR lpModuleName);\n"
"/* UNICODE version */\n"
"HMODULE GetModuleHandleW(LPCWSTR lpModuleName);"
msgstr ""
msgid "*windll* does not try to select one of them by magic, you must access the version you need by specifying ``GetModuleHandleA`` or ``GetModuleHandleW`` explicitly, and then call it with bytes or string objects respectively."
msgstr ""
msgid "Sometimes, dlls export functions with names which aren't valid Python identifiers, like ``\"??2@YAPAXI@Z\"``. In this case you have to use :func:`getattr` to retrieve the function::"
msgstr ""
msgid ""
">>> getattr(cdll.msvcrt, \"??2@YAPAXI@Z\")\n"
"<_FuncPtr object at 0x...>\n"
">>>"
msgstr ""
msgid "On Windows, some dlls export functions not by name but by ordinal. These functions can be accessed by indexing the dll object with the ordinal number::"
msgstr ""
msgid ""
">>> cdll.kernel32[1]\n"
"<_FuncPtr object at 0x...>\n"
">>> cdll.kernel32[0]\n"
"Traceback (most recent call last):\n"
" File \"<stdin>\", line 1, in <module>\n"
" File \"ctypes.py\", line 310, in __getitem__\n"
" func = _StdcallFuncPtr(name, self)\n"
"AttributeError: function ordinal 0 not found\n"
">>>"
msgstr ""
msgid "Calling functions"
msgstr ""
msgid "You can call these functions like any other Python callable. This example uses the ``rand()`` function, which takes no arguments and returns a pseudo-random integer::"
msgstr ""
msgid ""
">>> print(libc.rand())\n"
"1804289383"
msgstr ""
msgid "On Windows, you can call the ``GetModuleHandleA()`` function, which returns a win32 module handle (passing ``None`` as single argument to call it with a ``NULL`` pointer)::"
msgstr ""
msgid ""
">>> print(hex(windll.kernel32.GetModuleHandleA(None)))\n"
"0x1d000000\n"
">>>"
msgstr ""
msgid ":exc:`ValueError` is raised when you call an ``stdcall`` function with the ``cdecl`` calling convention, or vice versa::"
msgstr ""
msgid ""
">>> cdll.kernel32.GetModuleHandleA(None)\n"
"Traceback (most recent call last):\n"
" File \"<stdin>\", line 1, in <module>\n"
"ValueError: Procedure probably called with not enough arguments (4 bytes missing)\n"
">>>\n"
"\n"
">>> windll.msvcrt.printf(b\"spam\")\n"
"Traceback (most recent call last):\n"
" File \"<stdin>\", line 1, in <module>\n"
"ValueError: Procedure probably called with too many arguments (4 bytes in excess)\n"
">>>"
msgstr ""
msgid "To find out the correct calling convention you have to look into the C header file or the documentation for the function you want to call."
msgstr ""
msgid "On Windows, :mod:`!ctypes` uses win32 structured exception handling to prevent crashes from general protection faults when functions are called with invalid argument values::"
msgstr ""
msgid ""
">>> windll.kernel32.GetModuleHandleA(32)\n"
"Traceback (most recent call last):\n"
" File \"<stdin>\", line 1, in <module>\n"
"OSError: exception: access violation reading 0x00000020\n"
">>>"
msgstr ""
msgid "The :mod:`faulthandler` module can help debug crashes, such as segmentation faults produced by erroneous C library calls."
msgstr ""
msgid "``None``, integers, bytes objects and (unicode) strings are the only native Python objects that can directly be used as parameters in these function calls. ``None`` is passed as a C ``NULL`` pointer, bytes objects and strings are passed as pointer to the memory block that contains their data (:c:expr:`char *` or :c:expr:`wchar_t *`). Python integers are passed as the platform's default C :c:expr:`int` type, their value is masked to fit into the C type."
msgstr ""
msgid "Before we move on calling functions with other parameter types, we have to learn more about :mod:`!ctypes` data types."
msgstr ""
msgid "Fundamental data types"
msgstr ""
msgid ":mod:`!ctypes` defines a number of primitive C compatible data types:"
msgstr ""
msgid "ctypes type"
msgstr ""
msgid "C type"
msgstr ""
msgid "Python type"
msgstr ""
msgid ":py:attr:`~_SimpleCData._type_`"
msgstr ""
msgid ":class:`c_bool`"
msgstr ""
msgid ":c:expr:`_Bool`"
msgstr ""
msgid ":py:class:`bool`"
msgstr ""
msgid "``'?'``"
msgstr ""
msgid ":class:`c_char`"
msgstr ""
msgid ":c:expr:`char`"
msgstr ""
msgid "1-character :py:class:`bytes`"
msgstr ""
msgid "``'c'``"
msgstr ""
msgid ":class:`c_wchar`"
msgstr ""
msgid ":c:type:`wchar_t`"
msgstr ""
msgid "1-character :py:class:`str`"
msgstr ""
msgid "``'u'``"
msgstr ""
msgid ":class:`c_byte`"
msgstr ""
msgid ":py:class:`int`"
msgstr ""
msgid "``'b'``"
msgstr ""
msgid ":class:`c_ubyte`"
msgstr ""
msgid ":c:expr:`unsigned char`"
msgstr ""
msgid "``'B'``"
msgstr ""
msgid ":class:`c_short`"
msgstr ""
msgid ":c:expr:`short`"
msgstr ""
msgid "``'h'``"
msgstr ""
msgid ":class:`c_ushort`"
msgstr ""
msgid ":c:expr:`unsigned short`"
msgstr ""
msgid "``'H'``"
msgstr ""
msgid ":class:`c_int`"
msgstr ""
msgid ":c:expr:`int`"
msgstr ""
msgid "``'i'`` \\*"
msgstr ""
msgid ":class:`c_int8`"
msgstr ""
msgid ":c:type:`int8_t`"
msgstr ""
msgid "\\*"
msgstr ""
msgid ":class:`c_int16`"
msgstr ""
msgid ":c:type:`int16_t`"
msgstr ""
msgid ":class:`c_int32`"
msgstr ""
msgid ":c:type:`int32_t`"
msgstr ""
msgid ":class:`c_int64`"
msgstr ""
msgid ":c:type:`int64_t`"
msgstr ""
msgid ":class:`c_uint`"
msgstr ""
msgid ":c:expr:`unsigned int`"
msgstr ""
msgid "``'I'`` \\*"
msgstr ""
msgid ":class:`c_uint8`"
msgstr ""
msgid ":c:type:`uint8_t`"
msgstr ""
msgid ":class:`c_uint16`"
msgstr ""
msgid ":c:type:`uint16_t`"
msgstr ""
msgid ":class:`c_uint32`"
msgstr ""
msgid ":c:type:`uint32_t`"
msgstr ""
msgid ":class:`c_uint64`"
msgstr ""
msgid ":c:type:`uint64_t`"
msgstr ""
msgid ":class:`c_long`"
msgstr ""
msgid ":c:expr:`long`"
msgstr ""
msgid "``'l'``"
msgstr ""
msgid ":class:`c_ulong`"
msgstr ""
msgid ":c:expr:`unsigned long`"
msgstr ""
msgid "``'L'``"
msgstr ""
msgid ":class:`c_longlong`"
msgstr ""
msgid ":c:expr:`long long`"
msgstr ""
msgid "``'q'`` \\*"
msgstr ""
msgid ":class:`c_ulonglong`"
msgstr ""
msgid ":c:expr:`unsigned long long`"
msgstr ""
msgid "``'Q'`` \\*"
msgstr ""
msgid ":class:`c_size_t`"
msgstr ""
msgid ":c:type:`size_t`"
msgstr ""
msgid ":class:`c_ssize_t`"
msgstr ""
msgid ":c:type:`Py_ssize_t`"
msgstr ""
msgid ":class:`c_time_t`"
msgstr ""
msgid ":c:type:`time_t`"
msgstr ""
msgid ":class:`c_float`"
msgstr ""
msgid ":c:expr:`float`"
msgstr ""
msgid ":py:class:`float`"
msgstr ""
msgid "``'f'``"
msgstr ""
msgid ":class:`c_double`"
msgstr ""
msgid ":c:expr:`double`"
msgstr ""
msgid "``'d'``"
msgstr ""
msgid ":class:`c_longdouble`"
msgstr ""
msgid ":c:expr:`long double`"
msgstr ""
msgid "``'g'`` \\*"
msgstr ""
msgid ":class:`c_char_p`"
msgstr ""
msgid ":c:expr:`char *` (NUL terminated)"
msgstr ""
msgid ":py:class:`bytes` or ``None``"
msgstr ""
msgid "``'z'``"
msgstr ""
msgid ":class:`c_wchar_p`"
msgstr ""
msgid ":c:expr:`wchar_t *` (NUL terminated)"
msgstr ""
msgid ":py:class:`str` or ``None``"
msgstr ""
msgid "``'Z'``"
msgstr ""
msgid ":class:`c_void_p`"
msgstr ""
msgid ":c:expr:`void *`"
msgstr ""
msgid ":py:class:`int` or ``None``"
msgstr ""
msgid "``'P'``"
msgstr ""
msgid ":class:`py_object`"
msgstr ""
msgid ":c:expr:`PyObject *`"
msgstr ""
msgid ":py:class:`object`"
msgstr ""
msgid "``'O'``"
msgstr ""
msgid ":ref:`VARIANT_BOOL <ctypes-wintypes>`"
msgstr ""
msgid ":c:expr:`short int`"
msgstr ""
msgid "``'v'``"
msgstr ""
msgid "Additionally, if IEC 60559 compatible complex arithmetic (Annex G) is supported in both C and ``libffi``, the following complex types are available:"
msgstr ""
msgid ":class:`c_float_complex`"
msgstr ""
msgid ":c:expr:`float complex`"
msgstr ""
msgid ":py:class:`complex`"
msgstr ""
msgid "``'F'``"
msgstr ""
msgid ":class:`c_double_complex`"
msgstr ""
msgid ":c:expr:`double complex`"
msgstr ""
msgid "``'D'``"
msgstr ""
msgid ":class:`c_longdouble_complex`"
msgstr ""
msgid ":c:expr:`long double complex`"
msgstr ""
msgid "``'G'``"
msgstr ""
msgid "All these types can be created by calling them with an optional initializer of the correct type and value::"
msgstr ""
msgid ""
">>> c_int()\n"
"c_long(0)\n"
">>> c_wchar_p(\"Hello, World\")\n"
"c_wchar_p(140018365411392)\n"
">>> c_ushort(-3)\n"
"c_ushort(65533)\n"
">>>"
msgstr ""
msgid "The constructors for numeric types will convert input using :py:meth:`~object.__bool__`, :py:meth:`~object.__index__` (for ``int``), :py:meth:`~object.__float__` or :py:meth:`~object.__complex__`. This means :py:class:`~ctypes.c_bool` accepts any object with a truth value::"
msgstr ""
msgid ""
">>> empty_list = []\n"
">>> c_bool(empty_list)\n"
"c_bool(False)"
msgstr ""
msgid "Since these types are mutable, their value can also be changed afterwards::"
msgstr ""
msgid ""
">>> i = c_int(42)\n"
">>> print(i)\n"
"c_long(42)\n"
">>> print(i.value)\n"
"42\n"
">>> i.value = -99\n"
">>> print(i.value)\n"
"-99\n"
">>>"
msgstr ""
msgid "Assigning a new value to instances of the pointer types :class:`c_char_p`, :class:`c_wchar_p`, and :class:`c_void_p` changes the *memory location* they point to, *not the contents* of the memory block (of course not, because Python string objects are immutable)::"
msgstr ""
msgid ""
">>> s = \"Hello, World\"\n"
">>> c_s = c_wchar_p(s)\n"
">>> print(c_s)\n"
"c_wchar_p(139966785747344)\n"
">>> print(c_s.value)\n"
"Hello World\n"
">>> c_s.value = \"Hi, there\"\n"
">>> print(c_s) # the memory location has changed\n"
"c_wchar_p(139966783348904)\n"
">>> print(c_s.value)\n"
"Hi, there\n"
">>> print(s) # first object is unchanged\n"
"Hello, World\n"
">>>"
msgstr ""
msgid "You should be careful, however, not to pass them to functions expecting pointers to mutable memory. If you need mutable memory blocks, ctypes has a :func:`create_string_buffer` function which creates these in various ways. The current memory block contents can be accessed (or changed) with the ``raw`` property; if you want to access it as NUL terminated string, use the ``value`` property::"
msgstr ""
msgid ""
">>> from ctypes import *\n"
">>> p = create_string_buffer(3) # create a 3 byte buffer, initialized to NUL bytes\n"
">>> print(sizeof(p), repr(p.raw))\n"
"3 b'\\x00\\x00\\x00'\n"
">>> p = create_string_buffer(b\"Hello\") # create a buffer containing a NUL terminated string\n"
">>> print(sizeof(p), repr(p.raw))\n"
"6 b'Hello\\x00'\n"
">>> print(repr(p.value))\n"
"b'Hello'\n"
">>> p = create_string_buffer(b\"Hello\", 10) # create a 10 byte buffer\n"
">>> print(sizeof(p), repr(p.raw))\n"
"10 b'Hello\\x00\\x00\\x00\\x00\\x00'\n"
">>> p.value = b\"Hi\"\n"
">>> print(sizeof(p), repr(p.raw))\n"
"10 b'Hi\\x00lo\\x00\\x00\\x00\\x00\\x00'\n"
">>>"
msgstr ""
msgid "The :func:`create_string_buffer` function replaces the old :func:`!c_buffer` function (which is still available as an alias). To create a mutable memory block containing unicode characters of the C type :c:type:`wchar_t`, use the :func:`create_unicode_buffer` function."
msgstr ""
msgid "Calling functions, continued"
msgstr ""
msgid "Note that printf prints to the real standard output channel, *not* to :data:`sys.stdout`, so these examples will only work at the console prompt, not from within *IDLE* or *PythonWin*::"
msgstr ""
msgid ""
">>> printf = libc.printf\n"
">>> printf(b\"Hello, %s\\n\", b\"World!\")\n"
"Hello, World!\n"
"14\n"
">>> printf(b\"Hello, %S\\n\", \"World!\")\n"
"Hello, World!\n"
"14\n"
">>> printf(b\"%d bottles of beer\\n\", 42)\n"
"42 bottles of beer\n"
"19\n"
">>> printf(b\"%f bottles of beer\\n\", 42.5)\n"
"Traceback (most recent call last):\n"
" File \"<stdin>\", line 1, in <module>\n"
"ctypes.ArgumentError: argument 2: TypeError: Don't know how to convert parameter 2\n"
">>>"
msgstr ""
msgid "As has been mentioned before, all Python types except integers, strings, and bytes objects have to be wrapped in their corresponding :mod:`!ctypes` type, so that they can be converted to the required C data type::"
msgstr ""
msgid ""
">>> printf(b\"An int %d, a double %f\\n\", 1234, c_double(3.14))\n"
"An int 1234, a double 3.140000\n"
"31\n"
">>>"
msgstr ""
msgid "Calling variadic functions"
msgstr ""
msgid "On a lot of platforms calling variadic functions through ctypes is exactly the same as calling functions with a fixed number of parameters. On some platforms, and in particular ARM64 for Apple Platforms, the calling convention for variadic functions is different than that for regular functions."
msgstr ""
msgid "On those platforms it is required to specify the :attr:`~_CFuncPtr.argtypes` attribute for the regular, non-variadic, function arguments:"
msgstr ""
msgid "libc.printf.argtypes = [ctypes.c_char_p]"
msgstr ""
msgid "Because specifying the attribute does not inhibit portability it is advised to always specify :attr:`~_CFuncPtr.argtypes` for all variadic functions."
msgstr ""
msgid "Calling functions with your own custom data types"
msgstr ""
msgid "You can also customize :mod:`!ctypes` argument conversion to allow instances of your own classes be used as function arguments. :mod:`!ctypes` looks for an :attr:`!_as_parameter_` attribute and uses this as the function argument. The attribute must be an integer, string, bytes, a :mod:`!ctypes` instance, or an object with an :attr:`!_as_parameter_` attribute::"
msgstr ""
msgid ""
">>> class Bottles:\n"
"... def __init__(self, number):\n"
"... self._as_parameter_ = number\n"
"...\n"
">>> bottles = Bottles(42)\n"
">>> printf(b\"%d bottles of beer\\n\", bottles)\n"
"42 bottles of beer\n"
"19\n"
">>>"
msgstr ""
msgid "If you don't want to store the instance's data in the :attr:`!_as_parameter_` instance variable, you could define a :class:`property` which makes the attribute available on request."
msgstr ""
msgid "Specifying the required argument types (function prototypes)"
msgstr ""
msgid "It is possible to specify the required argument types of functions exported from DLLs by setting the :attr:`~_CFuncPtr.argtypes` attribute."
msgstr ""
msgid ":attr:`~_CFuncPtr.argtypes` must be a sequence of C data types (the :func:`!printf` function is probably not a good example here, because it takes a variable number and different types of parameters depending on the format string, on the other hand this is quite handy to experiment with this feature)::"
msgstr ""
msgid ""
">>> printf.argtypes = [c_char_p, c_char_p, c_int, c_double]\n"
">>> printf(b\"String '%s', Int %d, Double %f\\n\", b\"Hi\", 10, 2.2)\n"
"String 'Hi', Int 10, Double 2.200000\n"
"37\n"
">>>"
msgstr ""
msgid "Specifying a format protects against incompatible argument types (just as a prototype for a C function), and tries to convert the arguments to valid types::"
msgstr ""
msgid ""
">>> printf(b\"%d %d %d\", 1, 2, 3)\n"
"Traceback (most recent call last):\n"
" File \"<stdin>\", line 1, in <module>\n"
"ctypes.ArgumentError: argument 2: TypeError: 'int' object cannot be interpreted as ctypes.c_char_p\n"
">>> printf(b\"%s %d %f\\n\", b\"X\", 2, 3)\n"
"X 2 3.000000\n"
"13\n"
">>>"
msgstr ""
msgid "If you have defined your own classes which you pass to function calls, you have to implement a :meth:`~_CData.from_param` class method for them to be able to use them in the :attr:`~_CFuncPtr.argtypes` sequence. The :meth:`~_CData.from_param` class method receives the Python object passed to the function call, it should do a typecheck or whatever is needed to make sure this object is acceptable, and then return the object itself, its :attr:`!_as_parameter_` attribute, or whatever you want to pass as the C function argument in this case. Again, the result should be an integer, string, bytes, a :mod:`!ctypes` instance, or an object with an :attr:`!_as_parameter_` attribute."
msgstr ""
msgid "Return types"
msgstr ""
msgid "By default functions are assumed to return the C :c:expr:`int` type. Other return types can be specified by setting the :attr:`~_CFuncPtr.restype` attribute of the function object."
msgstr ""
msgid "The C prototype of :c:func:`time` is ``time_t time(time_t *)``. Because :c:type:`time_t` might be of a different type than the default return type :c:expr:`int`, you should specify the :attr:`!restype` attribute::"
msgstr ""
msgid ">>> libc.time.restype = c_time_t"
msgstr ""
msgid "The argument types can be specified using :attr:`~_CFuncPtr.argtypes`::"
msgstr ""
msgid ">>> libc.time.argtypes = (POINTER(c_time_t),)"
msgstr ""
msgid "To call the function with a ``NULL`` pointer as first argument, use ``None``::"
msgstr ""
msgid ""
">>> print(libc.time(None))\n"
"1150640792"
msgstr ""
msgid "Here is a more advanced example, it uses the :func:`!strchr` function, which expects a string pointer and a char, and returns a pointer to a string::"
msgstr ""
msgid ""
">>> strchr = libc.strchr\n"
">>> strchr(b\"abcdef\", ord(\"d\"))\n"
"8059983\n"
">>> strchr.restype = c_char_p # c_char_p is a pointer to a string\n"
">>> strchr(b\"abcdef\", ord(\"d\"))\n"
"b'def'\n"
">>> print(strchr(b\"abcdef\", ord(\"x\")))\n"
"None\n"
">>>"
msgstr ""
msgid "If you want to avoid the :func:`ord(\"x\") <ord>` calls above, you can set the :attr:`~_CFuncPtr.argtypes` attribute, and the second argument will be converted from a single character Python bytes object into a C char:"
msgstr ""
msgid ""
">>> strchr.restype = c_char_p\n"
">>> strchr.argtypes = [c_char_p, c_char]\n"
">>> strchr(b\"abcdef\", b\"d\")\n"
"b'def'\n"
">>> strchr(b\"abcdef\", b\"def\")\n"
"Traceback (most recent call last):\n"
"ctypes.ArgumentError: argument 2: TypeError: one character bytes, bytearray or integer expected\n"
">>> print(strchr(b\"abcdef\", b\"x\"))\n"
"None\n"
">>> strchr(b\"abcdef\", b\"d\")\n"
"b'def'\n"
">>>"
msgstr ""
msgid "You can also use a callable Python object (a function or a class for example) as the :attr:`~_CFuncPtr.restype` attribute, if the foreign function returns an integer. The callable will be called with the *integer* the C function returns, and the result of this call will be used as the result of your function call. This is useful to check for error return values and automatically raise an exception::"
msgstr ""
msgid ""
">>> GetModuleHandle = windll.kernel32.GetModuleHandleA\n"
">>> def ValidHandle(value):\n"
"... if value == 0:\n"
"... raise WinError()\n"
"... return value\n"
"...\n"
">>>\n"
">>> GetModuleHandle.restype = ValidHandle\n"
">>> GetModuleHandle(None)\n"
"486539264\n"
">>> GetModuleHandle(\"something silly\")\n"
"Traceback (most recent call last):\n"
" File \"<stdin>\", line 1, in <module>\n"
" File \"<stdin>\", line 3, in ValidHandle\n"
"OSError: [Errno 126] The specified module could not be found.\n"
">>>"
msgstr ""
msgid "``WinError`` is a function which will call Windows ``FormatMessage()`` api to get the string representation of an error code, and *returns* an exception. ``WinError`` takes an optional error code parameter, if no one is used, it calls :func:`GetLastError` to retrieve it."
msgstr ""
msgid "Please note that a much more powerful error checking mechanism is available through the :attr:`~_CFuncPtr.errcheck` attribute; see the reference manual for details."
msgstr ""
msgid "Passing pointers (or: passing parameters by reference)"
msgstr ""
msgid "Sometimes a C api function expects a *pointer* to a data type as parameter, probably to write into the corresponding location, or if the data is too large to be passed by value. This is also known as *passing parameters by reference*."
msgstr ""
msgid ":mod:`!ctypes` exports the :func:`byref` function which is used to pass parameters by reference. The same effect can be achieved with the :func:`pointer` function, although :func:`pointer` does a lot more work since it constructs a real pointer object, so it is faster to use :func:`byref` if you don't need the pointer object in Python itself::"
msgstr ""
msgid ""
">>> i = c_int()\n"
">>> f = c_float()\n"
">>> s = create_string_buffer(b'\\000' * 32)\n"
">>> print(i.value, f.value, repr(s.value))\n"
"0 0.0 b''\n"
">>> libc.sscanf(b\"1 3.14 Hello\", b\"%d %f %s\",\n"
"... byref(i), byref(f), s)\n"
"3\n"
">>> print(i.value, f.value, repr(s.value))\n"
"1 3.1400001049 b'Hello'\n"
">>>"
msgstr ""
msgid "Structures and unions"
msgstr ""
msgid "Structures and unions must derive from the :class:`Structure` and :class:`Union` base classes which are defined in the :mod:`!ctypes` module. Each subclass must define a :attr:`~Structure._fields_` attribute. :attr:`!_fields_` must be a list of *2-tuples*, containing a *field name* and a *field type*."
msgstr ""
msgid "The field type must be a :mod:`!ctypes` type like :class:`c_int`, or any other derived :mod:`!ctypes` type: structure, union, array, pointer."
msgstr ""
msgid "Here is a simple example of a POINT structure, which contains two integers named *x* and *y*, and also shows how to initialize a structure in the constructor::"
msgstr ""
msgid ""
">>> from ctypes import *\n"
">>> class POINT(Structure):\n"
"... _fields_ = [(\"x\", c_int),\n"
"... (\"y\", c_int)]\n"
"...\n"
">>> point = POINT(10, 20)\n"
">>> print(point.x, point.y)\n"
"10 20\n"
">>> point = POINT(y=5)\n"
">>> print(point.x, point.y)\n"
"0 5\n"
">>> POINT(1, 2, 3)\n"
"Traceback (most recent call last):\n"
" File \"<stdin>\", line 1, in <module>\n"
"TypeError: too many initializers\n"
">>>"
msgstr ""
msgid "You can, however, build much more complicated structures. A structure can itself contain other structures by using a structure as a field type."
msgstr ""
msgid "Here is a RECT structure which contains two POINTs named *upperleft* and *lowerright*::"
msgstr ""
msgid ""
">>> class RECT(Structure):\n"
"... _fields_ = [(\"upperleft\", POINT),\n"
"... (\"lowerright\", POINT)]\n"
"...\n"
">>> rc = RECT(point)\n"
">>> print(rc.upperleft.x, rc.upperleft.y)\n"
"0 5\n"
">>> print(rc.lowerright.x, rc.lowerright.y)\n"
"0 0\n"
">>>"
msgstr ""
msgid "Nested structures can also be initialized in the constructor in several ways::"
msgstr ""
msgid ""
">>> r = RECT(POINT(1, 2), POINT(3, 4))\n"
">>> r = RECT((1, 2), (3, 4))"
msgstr ""
msgid "Field :term:`descriptor`\\s can be retrieved from the *class*, they are useful for debugging because they can provide useful information. See :class:`CField`::"
msgstr ""
msgid ""
">>> POINT.x\n"
"<ctypes.CField 'x' type=c_int, ofs=0, size=4>\n"
">>> POINT.y\n"
"<ctypes.CField 'y' type=c_int, ofs=4, size=4>\n"
">>>"
msgstr ""
msgid ":mod:`!ctypes` does not support passing unions or structures with bit-fields to functions by value. While this may work on 32-bit x86, it's not guaranteed by the library to work in the general case. Unions and structures with bit-fields should always be passed to functions by pointer."
msgstr ""
msgid "Structure/union layout, alignment and byte order"
msgstr ""
msgid "By default, Structure and Union fields are laid out in the same way the C compiler does it. It is possible to override this behavior entirely by specifying a :attr:`~Structure._layout_` class attribute in the subclass definition; see the attribute documentation for details."
msgstr ""
msgid "It is possible to specify the maximum alignment for the fields and/or for the structure itself by setting the class attributes :attr:`~Structure._pack_` and/or :attr:`~Structure._align_`, respectively. See the attribute documentation for details."
msgstr ""
msgid ":mod:`!ctypes` uses the native byte order for Structures and Unions. To build structures with non-native byte order, you can use one of the :class:`BigEndianStructure`, :class:`LittleEndianStructure`, :class:`BigEndianUnion`, and :class:`LittleEndianUnion` base classes. These classes cannot contain pointer fields."
msgstr ""
msgid "Bit fields in structures and unions"
msgstr ""
msgid "It is possible to create structures and unions containing bit fields. Bit fields are only possible for integer fields, the bit width is specified as the third item in the :attr:`~Structure._fields_` tuples::"
msgstr ""
msgid ""
">>> class Int(Structure):\n"
"... _fields_ = [(\"first_16\", c_int, 16),\n"
"... (\"second_16\", c_int, 16)]\n"
"...\n"
">>> print(Int.first_16)\n"
"<ctypes.CField 'first_16' type=c_int, ofs=0, bit_size=16, bit_offset=0>\n"
">>> print(Int.second_16)\n"
"<ctypes.CField 'second_16' type=c_int, ofs=0, bit_size=16, bit_offset=16>"
msgstr ""
msgid "It is important to note that bit field allocation and layout in memory are not defined as a C standard; their implementation is compiler-specific. By default, Python will attempt to match the behavior of a \"native\" compiler for the current platform. See the :attr:`~Structure._layout_` attribute for details on the default behavior and how to change it."
msgstr ""
msgid "Arrays"
msgstr ""
msgid "Arrays are sequences, containing a fixed number of instances of the same type."
msgstr ""
msgid "The recommended way to create array types is by multiplying a data type with a positive integer::"
msgstr ""
msgid "TenPointsArrayType = POINT * 10"
msgstr ""
msgid "Here is an example of a somewhat artificial data type, a structure containing 4 POINTs among other stuff::"
msgstr ""
msgid ""
">>> from ctypes import *\n"
">>> class POINT(Structure):\n"
"... _fields_ = (\"x\", c_int), (\"y\", c_int)\n"
"...\n"
">>> class MyStruct(Structure):\n"
"... _fields_ = [(\"a\", c_int),\n"
"... (\"b\", c_float),\n"
"... (\"point_array\", POINT * 4)]\n"
">>>\n"
">>> print(len(MyStruct().point_array))\n"
"4\n"
">>>"
msgstr ""
msgid "Instances are created in the usual way, by calling the class::"
msgstr ""
msgid ""
"arr = TenPointsArrayType()\n"
"for pt in arr:\n"
" print(pt.x, pt.y)"
msgstr ""
msgid "The above code print a series of ``0 0`` lines, because the array contents is initialized to zeros."
msgstr ""
msgid "Initializers of the correct type can also be specified::"
msgstr ""
msgid ""