forked from zhaojh329/lua-ffi
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathlua-ffi.html
More file actions
712 lines (668 loc) · 53.2 KB
/
lua-ffi.html
File metadata and controls
712 lines (668 loc) · 53.2 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
<!doctype html>
<html>
<head>
<meta charset='UTF-8'><meta name='viewport' content='width=device-width initial-scale=1'><style type='text/css'>html {overflow-x: initial !important;}</style>
<style type='text/css' id="style-base">:root { --bg-color: #ffffff; --text-color: #333333; --select-text-bg-color: #B5D6FC; --select-text-font-color: auto; --monospace: "Lucida Console",Consolas,"Courier",monospace; --title-bar-height: 20px; }
.mac-os-11 { --title-bar-height: 28px; }
html { font-size: 14px; background-color: var(--bg-color); color: var(--text-color); font-family: "Helvetica Neue", Helvetica, Arial, "Segoe UI Emoji", "SF Pro", sans-serif; -webkit-font-smoothing: antialiased; }
h1, h2, h3, h4, h5 { white-space: pre-wrap; }
body { margin: 0px; padding: 0px; height: auto; inset: 0px; font-size: 1rem; line-height: 1.42857; overflow-x: hidden; background: inherit; }
iframe { margin: auto; }
a.url { word-break: break-all; }
a:active, a:hover { outline: 0px; }
.in-text-selection, ::selection { text-shadow: none; background: var(--select-text-bg-color); color: var(--select-text-font-color); }
#write { margin: 0px auto; height: auto; width: inherit; word-break: normal; overflow-wrap: break-word; position: relative; white-space: normal; overflow-x: visible; padding-top: 36px; }
#write.first-line-indent p { text-indent: 2em; }
#write.first-line-indent li p, #write.first-line-indent p *, #write.first-line-indent svg * { text-indent: 0px; }
#write.first-line-indent li { margin-left: 2em; }
.for-image #write { padding-left: 8px; padding-right: 8px; }
body.typora-export { padding-left: 30px; padding-right: 30px; }
.typora-export .footnote-line, .typora-export li, .typora-export p { white-space: pre-wrap; }
.typora-export .task-list-item input { pointer-events: none; }
@media screen and (max-width: 500px) {
body.typora-export { padding-left: 0px; padding-right: 0px; }
#write { padding-left: 20px; padding-right: 20px; }
}
#write li > figure:last-child { margin-bottom: 0.5rem; }
#write ol, #write ul { position: relative; }
img { max-width: 100%; vertical-align: middle; image-orientation: from-image; }
button, input, select, textarea { color: inherit; font: inherit; }
input[type="checkbox"], input[type="radio"] { line-height: normal; padding: 0px; }
*, ::after, ::before { box-sizing: border-box; }
#write h1, #write h2, #write h3, #write h4, #write h5, #write h6, #write p, #write pre { width: inherit; position: relative; }
#write svg h1, #write svg h2, #write svg h3, #write svg h4, #write svg h5, #write svg h6, #write svg p { position: static; }
.nodeLabel p { padding-right: 2px; padding-left: 2px; }
.typora-export .nodeLabel p { padding-right: 0px; padding-left: 0px; }
foreignobject { overflow: visible; }
p { line-height: inherit; }
h1, h2, h3, h4, h5, h6 { break-after: avoid-page; break-inside: avoid; orphans: 4; }
p { orphans: 4; }
li p { orphans: 1; }
h1 { font-size: 2rem; }
h2 { font-size: 1.8rem; }
h3 { font-size: 1.6rem; }
h4 { font-size: 1.4rem; }
h5 { font-size: 1.2rem; }
h6 { font-size: 1rem; }
.md-math-block, .md-rawblock, h1, h2, h3, h4, h5, h6, p { margin-top: 1rem; margin-bottom: 1rem; }
.hidden { display: none; }
.md-blockmeta { color: rgb(204, 204, 204); font-weight: 700; font-style: italic; }
a { cursor: pointer; }
sup.md-footnote { padding: 2px 4px; background-color: rgba(238, 238, 238, 0.7); color: rgb(85, 85, 85); border-radius: 4px; cursor: pointer; }
sup.md-footnote a, sup.md-footnote a:hover { color: inherit; text-transform: inherit; text-decoration: inherit; }
#write input[type="checkbox"] { cursor: pointer; width: inherit; height: inherit; }
figure { overflow-x: auto; margin: 1.2em 0px; max-width: calc(100% + 16px); padding: 0px; }
figure > table { margin: 0px; }
thead, tr { break-inside: avoid; break-after: auto; }
thead { display: table-header-group; }
table { border-collapse: collapse; border-spacing: 0px; width: 100%; overflow: auto; break-inside: auto; text-align: left; }
table.md-table td { min-width: 32px; }
.CodeMirror-gutters { border-right: 0px; background-color: inherit; }
.CodeMirror-linenumber { user-select: none; }
.CodeMirror { text-align: left; }
.CodeMirror-placeholder { opacity: 0.3; }
.CodeMirror pre { padding: 0px 4px; }
.CodeMirror-lines { padding: 0px; }
div.hr:focus { cursor: none; }
#write pre { white-space: pre-wrap; }
#write.fences-no-line-wrapping pre { white-space: pre; }
#write pre.ty-contain-cm { white-space: normal; }
.CodeMirror-gutters { margin-right: 4px; }
.md-fences { font-size: 0.9rem; display: block; break-inside: avoid; text-align: left; overflow: visible; white-space: pre; background: inherit; position: relative !important; }
.md-fences-adv-panel { width: 100%; margin-top: 10px; text-align: center; padding-top: 0px; padding-bottom: 8px; overflow-x: auto; }
#write .md-fences.mock-cm { white-space: pre-wrap; }
.md-fences.md-fences-with-lineno { padding-left: 0px; }
#write.fences-no-line-wrapping .md-fences.mock-cm { white-space: pre; overflow-x: auto; }
.md-fences.mock-cm.md-fences-with-lineno { padding-left: 8px; }
.CodeMirror-line, twitterwidget { break-inside: avoid; }
svg { break-inside: avoid; }
.footnotes { opacity: 0.8; font-size: 0.9rem; margin-top: 1em; margin-bottom: 1em; }
.footnotes + .footnotes { margin-top: 0px; }
.md-reset { margin: 0px; padding: 0px; border: 0px; outline: 0px; vertical-align: top; background: 0px 0px; text-decoration: none; text-shadow: none; float: none; position: static; width: auto; height: auto; white-space: nowrap; cursor: inherit; -webkit-tap-highlight-color: transparent; line-height: normal; font-weight: 400; text-align: left; box-sizing: content-box; direction: ltr; }
li div { padding-top: 0px; }
blockquote { margin: 1rem 0px; }
li .mathjax-block, li p { margin: 0.5rem 0px; }
li blockquote { margin: 1rem 0px; }
li { margin: 0px; position: relative; }
blockquote > :last-child { margin-bottom: 0px; }
blockquote > :first-child, li > :first-child { margin-top: 0px; }
.footnotes-area { color: rgb(136, 136, 136); margin-top: 0.714rem; padding-bottom: 0.143rem; white-space: normal; }
#write .footnote-line { white-space: pre-wrap; }
@media print {
body, html { border: 1px solid transparent; height: 99%; break-after: avoid; break-before: avoid; font-variant-ligatures: no-common-ligatures; }
#write { margin-top: 0px; border-color: transparent !important; padding-top: 0px !important; padding-bottom: 0px !important; }
.typora-export * { -webkit-print-color-adjust: exact; }
.typora-export #write { break-after: avoid; }
.typora-export #write::after { height: 0px; }
.is-mac table { break-inside: avoid; }
#write > p:nth-child(1) { margin-top: 0px; }
.typora-export-show-outline .typora-export-sidebar { display: none; }
figure { overflow-x: visible; }
}
.footnote-line { margin-top: 0.714em; font-size: 0.7em; }
a img, img a { cursor: pointer; }
pre.md-meta-block { font-size: 0.8rem; min-height: 0.8rem; white-space: pre-wrap; background: rgb(204, 204, 204); display: block; overflow-x: hidden; }
p > .md-image:only-child:not(.md-img-error) img, p > img:only-child { display: block; margin: auto; }
#write.first-line-indent p > .md-image:only-child:not(.md-img-error) img { left: -2em; position: relative; }
p > .md-image:only-child { display: inline-block; width: 100%; }
#write .MathJax_Display { margin: 0.8em 0px 0px; }
.md-math-block { width: 100%; }
.md-math-block:not(:empty)::after { display: none; }
.MathJax_ref { fill: currentcolor; }
[contenteditable="true"]:active, [contenteditable="true"]:focus, [contenteditable="false"]:active, [contenteditable="false"]:focus { outline: 0px; box-shadow: none; }
.md-task-list-item { position: relative; list-style-type: none; }
.task-list-item.md-task-list-item { padding-left: 0px; }
.md-task-list-item > input { position: absolute; top: 0px; left: 0px; margin-left: -1.2em; margin-top: calc(1em - 10px); border: none; }
.math { font-size: 1rem; }
.md-toc { min-height: 3.58rem; position: relative; font-size: 0.9rem; border-radius: 10px; }
.md-toc-content { position: relative; margin-left: 0px; }
.md-toc-content::after, .md-toc::after { display: none; }
.md-toc-item { display: block; color: rgb(65, 131, 196); }
.md-toc-item a { text-decoration: none; }
.md-toc-inner:hover { text-decoration: underline; }
.md-toc-inner { display: inline-block; cursor: pointer; }
.md-toc-h1 .md-toc-inner { margin-left: 0px; font-weight: 700; }
.md-toc-h2 .md-toc-inner { margin-left: 2em; }
.md-toc-h3 .md-toc-inner { margin-left: 4em; }
.md-toc-h4 .md-toc-inner { margin-left: 6em; }
.md-toc-h5 .md-toc-inner { margin-left: 8em; }
.md-toc-h6 .md-toc-inner { margin-left: 10em; }
@media screen and (max-width: 48em) {
.md-toc-h3 .md-toc-inner { margin-left: 3.5em; }
.md-toc-h4 .md-toc-inner { margin-left: 5em; }
.md-toc-h5 .md-toc-inner { margin-left: 6.5em; }
.md-toc-h6 .md-toc-inner { margin-left: 8em; }
}
a.md-toc-inner { font-size: inherit; font-style: inherit; font-weight: inherit; line-height: inherit; }
.footnote-line a:not(.reversefootnote) { color: inherit; }
.reversefootnote { font-family: ui-monospace, sans-serif; }
.md-attr { display: none; }
.md-fn-count::after { content: "."; }
code, pre, samp, tt { font-family: var(--monospace); }
kbd { margin: 0px 0.1em; padding: 0.1em 0.6em; font-size: 0.8em; color: rgb(36, 39, 41); background: rgb(255, 255, 255); border: 1px solid rgb(173, 179, 185); border-radius: 3px; box-shadow: rgba(12, 13, 14, 0.2) 0px 1px 0px, rgb(255, 255, 255) 0px 0px 0px 2px inset; white-space: nowrap; vertical-align: middle; }
.md-comment { color: rgb(162, 127, 3); opacity: 0.6; font-family: var(--monospace); }
code { text-align: left; vertical-align: initial; }
a.md-print-anchor { white-space: pre !important; border-width: initial !important; border-style: none !important; border-color: initial !important; display: inline-block !important; position: absolute !important; width: 1px !important; right: 0px !important; outline: 0px !important; background: 0px 0px !important; text-decoration: initial !important; text-shadow: initial !important; }
.os-windows.monocolor-emoji .md-emoji { font-family: "Segoe UI Symbol", sans-serif; }
.md-diagram-panel > svg { max-width: 100%; }
[lang="flow"] svg, [lang="mermaid"] svg { max-width: 100%; height: auto; }
[lang="mermaid"] .node text { font-size: 1rem; }
table tr th { border-bottom: 0px; }
video { max-width: 100%; display: block; margin: 0px auto; }
iframe { max-width: 100%; width: 100%; border: none; }
.highlight td, .highlight tr { border: 0px; }
mark { background: rgb(255, 255, 0); color: rgb(0, 0, 0); }
.md-html-inline .md-plain, .md-html-inline strong, mark .md-inline-math, mark strong { color: inherit; }
.md-expand mark .md-meta { opacity: 0.3 !important; }
mark .md-meta { color: rgb(0, 0, 0); }
@media print {
.typora-export h1, .typora-export h2, .typora-export h3, .typora-export h4, .typora-export h5, .typora-export h6 { break-inside: avoid; }
}
.md-diagram-panel .messageText { stroke: none !important; }
.md-diagram-panel .start-state { fill: var(--node-fill); }
.md-diagram-panel .edgeLabel rect { opacity: 1 !important; }
.md-fences.md-fences-math { font-size: 1em; }
.md-fences-advanced:not(.md-focus) { padding: 0px; white-space: nowrap; border: 0px; }
.md-fences-advanced:not(.md-focus) { background: inherit; }
.mermaid-svg { margin: auto; }
.typora-export-show-outline .typora-export-content { max-width: 1440px; margin: auto; display: flex; flex-direction: row; }
.typora-export-sidebar { width: 300px; font-size: 0.8rem; margin-top: 80px; margin-right: 18px; }
.typora-export-show-outline #write { --webkit-flex: 2; flex: 2 1 0%; }
.typora-export-sidebar .outline-content { position: fixed; top: 0px; max-height: 100%; overflow: hidden auto; padding-bottom: 30px; padding-top: 60px; width: 300px; }
@media screen and (max-width: 1024px) {
.typora-export-sidebar, .typora-export-sidebar .outline-content { width: 240px; }
}
@media screen and (max-width: 800px) {
.typora-export-sidebar { display: none; }
}
.outline-content li, .outline-content ul { margin-left: 0px; margin-right: 0px; padding-left: 0px; padding-right: 0px; list-style: none; overflow-wrap: anywhere; }
.outline-content ul { margin-top: 0px; margin-bottom: 0px; }
.outline-content strong { font-weight: 400; }
.outline-expander { width: 1rem; height: 1.42857rem; position: relative; display: table-cell; vertical-align: middle; cursor: pointer; padding-left: 4px; }
.outline-expander::before { content: ""; position: relative; font-family: Ionicons; display: inline-block; font-size: 8px; vertical-align: middle; }
.outline-item { padding-top: 3px; padding-bottom: 3px; cursor: pointer; }
.outline-expander:hover::before { content: ""; }
.outline-h1 > .outline-item { padding-left: 0px; }
.outline-h2 > .outline-item { padding-left: 1em; }
.outline-h3 > .outline-item { padding-left: 2em; }
.outline-h4 > .outline-item { padding-left: 3em; }
.outline-h5 > .outline-item { padding-left: 4em; }
.outline-h6 > .outline-item { padding-left: 5em; }
.outline-label { cursor: pointer; display: table-cell; vertical-align: middle; text-decoration: none; color: inherit; }
.outline-label:hover { text-decoration: underline; }
.outline-item:hover { border-color: rgb(245, 245, 245); background-color: var(--item-hover-bg-color); }
.outline-item:hover { margin-left: -28px; margin-right: -28px; border-left: 28px solid transparent; border-right: 28px solid transparent; }
.outline-item-single .outline-expander::before, .outline-item-single .outline-expander:hover::before { display: none; }
.outline-item-open > .outline-item > .outline-expander::before { content: ""; }
.outline-children { display: none; }
.info-panel-tab-wrapper { display: none; }
.outline-item-open > .outline-children { display: block; }
.typora-export .outline-item { padding-top: 1px; padding-bottom: 1px; }
.typora-export .outline-item:hover { margin-right: -8px; border-right: 8px solid transparent; }
.typora-export .outline-expander::before { content: "+"; font-family: inherit; top: -1px; }
.typora-export .outline-expander:hover::before, .typora-export .outline-item-open > .outline-item > .outline-expander::before { content: "−"; }
.typora-export-collapse-outline .outline-children { display: none; }
.typora-export-collapse-outline .outline-item-open > .outline-children, .typora-export-no-collapse-outline .outline-children { display: block; }
.typora-export-no-collapse-outline .outline-expander::before { content: "" !important; }
.typora-export-show-outline .outline-item-active > .outline-item .outline-label { font-weight: 700; }
.md-inline-math-container mjx-container { zoom: 0.95; }
mjx-container { break-inside: avoid; }
.md-alert.md-alert-note { border-left-color: rgb(9, 105, 218); }
.md-alert.md-alert-important { border-left-color: rgb(130, 80, 223); }
.md-alert.md-alert-warning { border-left-color: rgb(154, 103, 0); }
.md-alert.md-alert-tip { border-left-color: rgb(31, 136, 61); }
.md-alert.md-alert-caution { border-left-color: rgb(207, 34, 46); }
.md-alert { padding: 0px 1em; margin-bottom: 16px; color: inherit; border-left: 0.25em solid rgb(0, 0, 0); }
.md-alert-text-note { color: rgb(9, 105, 218); }
.md-alert-text-important { color: rgb(130, 80, 223); }
.md-alert-text-warning { color: rgb(154, 103, 0); }
.md-alert-text-tip { color: rgb(31, 136, 61); }
.md-alert-text-caution { color: rgb(207, 34, 46); }
.md-alert-text { font-size: 0.9rem; font-weight: 700; }
.md-alert-text svg { fill: currentcolor; position: relative; top: 0.125em; margin-right: 1ch; overflow: visible; }
.md-alert-text-container::after { content: attr(data-text); text-transform: capitalize; pointer-events: none; margin-right: 1ch; }
</style>
<style type='text/css' id="style-codemirror">.CodeMirror { height: auto; }
.CodeMirror.cm-s-inner { background: inherit; }
.CodeMirror-scroll { overflow: auto hidden; z-index: 3; }
.CodeMirror-gutter-filler, .CodeMirror-scrollbar-filler { background-color: rgb(255, 255, 255); }
.CodeMirror-gutters { border-right: 1px solid rgb(221, 221, 221); background: inherit; white-space: nowrap; }
.CodeMirror-linenumber { padding: 0px 3px 0px 5px; text-align: right; color: rgb(153, 153, 153); }
.cm-s-inner .cm-keyword { color: rgb(119, 0, 136); }
.cm-s-inner .cm-atom, .cm-s-inner.cm-atom { color: rgb(34, 17, 153); }
.cm-s-inner .cm-number { color: rgb(17, 102, 68); }
.cm-s-inner .cm-def { color: rgb(0, 0, 255); }
.cm-s-inner .cm-variable { color: rgb(0, 0, 0); }
.cm-s-inner .cm-variable-2 { color: rgb(0, 85, 170); }
.cm-s-inner .cm-variable-3 { color: rgb(0, 136, 85); }
.cm-s-inner .cm-string { color: rgb(170, 17, 17); }
.cm-s-inner .cm-property { color: rgb(0, 0, 0); }
.cm-s-inner .cm-operator { color: rgb(152, 26, 26); }
.cm-s-inner .cm-comment, .cm-s-inner.cm-comment { color: rgb(170, 85, 0); }
.cm-s-inner .cm-string-2 { color: rgb(255, 85, 0); }
.cm-s-inner .cm-meta { color: rgb(85, 85, 85); }
.cm-s-inner .cm-qualifier { color: rgb(85, 85, 85); }
.cm-s-inner .cm-builtin { color: rgb(51, 0, 170); }
.cm-s-inner .cm-bracket { color: rgb(153, 153, 119); }
.cm-s-inner .cm-tag { color: rgb(17, 119, 0); }
.cm-s-inner .cm-attribute { color: rgb(0, 0, 204); }
.cm-s-inner .cm-header, .cm-s-inner.cm-header { color: rgb(0, 0, 255); }
.cm-s-inner .cm-quote, .cm-s-inner.cm-quote { color: rgb(0, 153, 0); }
.cm-s-inner .cm-hr, .cm-s-inner.cm-hr { color: rgb(153, 153, 153); }
.cm-s-inner .cm-link, .cm-s-inner.cm-link { color: rgb(0, 0, 204); }
.cm-negative { color: rgb(221, 68, 68); }
.cm-positive { color: rgb(34, 153, 34); }
.cm-header, .cm-strong { font-weight: 700; }
.cm-del { text-decoration: line-through; }
.cm-em { font-style: italic; }
.cm-link { text-decoration: underline; }
.cm-error { color: red; }
.cm-invalidchar { color: red; }
.cm-constant { color: rgb(38, 139, 210); }
.cm-defined { color: rgb(181, 137, 0); }
div.CodeMirror span.CodeMirror-matchingbracket { color: rgb(0, 255, 0); }
div.CodeMirror span.CodeMirror-nonmatchingbracket { color: rgb(255, 34, 34); }
.cm-s-inner .CodeMirror-activeline-background { background: inherit; }
.CodeMirror { position: relative; overflow: hidden; }
.CodeMirror-scroll { height: 100%; outline: 0px; position: relative; box-sizing: content-box; background: inherit; }
.CodeMirror-sizer { position: relative; }
.CodeMirror-gutter-filler, .CodeMirror-hscrollbar, .CodeMirror-scrollbar-filler, .CodeMirror-vscrollbar { position: absolute; z-index: 6; display: none; outline: 0px; }
.CodeMirror-vscrollbar { right: 0px; top: 0px; overflow: hidden; }
.CodeMirror-hscrollbar { bottom: 0px; left: 0px; overflow: auto hidden; }
.CodeMirror-scrollbar-filler { right: 0px; bottom: 0px; }
.CodeMirror-gutter-filler { left: 0px; bottom: 0px; }
.CodeMirror-gutters { position: absolute; left: 0px; top: 0px; padding-bottom: 10px; z-index: 3; overflow-y: hidden; }
.CodeMirror-gutter { white-space: normal; height: 100%; box-sizing: content-box; padding-bottom: 30px; margin-bottom: -32px; display: inline-block; }
.CodeMirror-gutter-wrapper { position: absolute; z-index: 4; background: 0px 0px !important; border: none !important; }
.CodeMirror-gutter-background { position: absolute; top: 0px; bottom: 0px; z-index: 4; }
.CodeMirror-gutter-elt { position: absolute; cursor: default; z-index: 4; }
.CodeMirror-lines { cursor: text; }
.CodeMirror pre { border-radius: 0px; border-width: 0px; background: 0px 0px; font-family: inherit; font-size: inherit; margin: 0px; white-space: pre; overflow-wrap: normal; color: inherit; z-index: 2; position: relative; overflow: visible; }
.CodeMirror-wrap pre { overflow-wrap: break-word; white-space: pre-wrap; word-break: normal; }
.CodeMirror-code pre { border-right: 30px solid transparent; width: fit-content; }
.CodeMirror-wrap .CodeMirror-code pre { border-right: none; width: auto; }
.CodeMirror-linebackground { position: absolute; inset: 0px; z-index: 0; }
.CodeMirror-linewidget { position: relative; z-index: 2; overflow: auto; }
.CodeMirror-wrap .CodeMirror-scroll { overflow-x: hidden; }
.CodeMirror-measure { position: absolute; width: 100%; height: 0px; overflow: hidden; visibility: hidden; }
.CodeMirror-measure pre { position: static; }
.CodeMirror div.CodeMirror-cursor { position: absolute; visibility: hidden; border-right: none; width: 0px; }
.CodeMirror div.CodeMirror-cursor { visibility: hidden; }
.CodeMirror-focused div.CodeMirror-cursor { visibility: inherit; }
.cm-searching { background: rgba(255, 255, 0, 0.4); }
span.cm-underlined { text-decoration: underline; }
span.cm-strikethrough { text-decoration: line-through; }
.cm-tw-syntaxerror { color: rgb(255, 255, 255); background-color: rgb(153, 0, 0); }
.cm-tw-deleted { text-decoration: line-through; }
.cm-tw-header5 { font-weight: 700; }
.cm-tw-listitem:first-child { padding-left: 10px; }
.cm-tw-box { border-style: solid; border-right-width: 1px; border-bottom-width: 1px; border-left-width: 1px; border-color: inherit; border-top-width: 0px !important; }
.cm-tw-underline { text-decoration: underline; }
@media print {
.CodeMirror div.CodeMirror-cursor { visibility: hidden; }
}
</style>
<link rel='stylesheet' href='https://fonts.googleapis.com/css?family=Open+Sans:400italic,700italic,700,400&subset=latin,latin-ext' type='text/css' />
<style type='text/css' id="style-theme_css">:root {
--side-bar-bg-color: #fafafa;
--control-text-color: #777;
}
@include-when-export url(https://fonts.googleapis.com/css?family=Open+Sans:400italic,700italic,700,400&subset=latin,latin-ext);
/* open-sans-regular - latin-ext_latin */
/* open-sans-italic - latin-ext_latin */
/* open-sans-700 - latin-ext_latin */
/* open-sans-700italic - latin-ext_latin */
html {
font-size: 16px;
-webkit-font-smoothing: antialiased;
}
body {
font-family: "Open Sans","Clear Sans", "Helvetica Neue", Helvetica, Arial, 'Segoe UI Emoji', 'SF Pro', sans-serif;
color: rgb(51, 51, 51);
line-height: 1.6;
}
#write {
max-width: 860px;
margin: 0 auto;
padding: 30px;
padding-bottom: 100px;
}
@media only screen and (min-width: 1400px) {
#write {
max-width: 1024px;
}
}
@media only screen and (min-width: 1800px) {
#write {
max-width: 1200px;
}
}
#write > ul:first-child,
#write > ol:first-child{
margin-top: 30px;
}
a {
color: #4183C4;
}
h1,
h2,
h3,
h4,
h5,
h6 {
position: relative;
margin-top: 1rem;
margin-bottom: 1rem;
font-weight: bold;
line-height: 1.4;
cursor: text;
}
h1:hover a.anchor,
h2:hover a.anchor,
h3:hover a.anchor,
h4:hover a.anchor,
h5:hover a.anchor,
h6:hover a.anchor {
text-decoration: none;
}
h1 tt,
h1 code {
font-size: inherit;
}
h2 tt,
h2 code {
font-size: inherit;
}
h3 tt,
h3 code {
font-size: inherit;
}
h4 tt,
h4 code {
font-size: inherit;
}
h5 tt,
h5 code {
font-size: inherit;
}
h6 tt,
h6 code {
font-size: inherit;
}
h1 {
font-size: 2.25em;
line-height: 1.2;
border-bottom: 1px solid #eee;
}
h2 {
font-size: 1.75em;
line-height: 1.225;
border-bottom: 1px solid #eee;
}
/*@media print {
.typora-export h1,
.typora-export h2 {
border-bottom: none;
padding-bottom: initial;
}
.typora-export h1::after,
.typora-export h2::after {
content: "";
display: block;
height: 100px;
margin-top: -96px;
border-top: 1px solid #eee;
}
}*/
h3 {
font-size: 1.5em;
line-height: 1.43;
}
h4 {
font-size: 1.25em;
}
h5 {
font-size: 1em;
}
h6 {
font-size: 1em;
color: #777;
}
p,
blockquote,
ul,
ol,
dl,
table{
margin: 0.8em 0;
}
li>ol,
li>ul {
margin: 0 0;
}
hr {
height: 2px;
padding: 0;
margin: 16px 0;
background-color: #e7e7e7;
border: 0 none;
overflow: hidden;
box-sizing: content-box;
}
li p.first {
display: inline-block;
}
ul,
ol {
padding-left: 30px;
}
ul:first-child,
ol:first-child {
margin-top: 0;
}
ul:last-child,
ol:last-child {
margin-bottom: 0;
}
blockquote {
border-left: 4px solid #dfe2e5;
padding: 0 15px;
color: #777777;
}
blockquote blockquote {
padding-right: 0;
}
table {
padding: 0;
word-break: initial;
}
table tr {
border: 1px solid #dfe2e5;
margin: 0;
padding: 0;
}
table tr:nth-child(2n),
thead {
background-color: #f8f8f8;
}
table th {
font-weight: bold;
border: 1px solid #dfe2e5;
border-bottom: 0;
margin: 0;
padding: 6px 13px;
}
table td {
border: 1px solid #dfe2e5;
margin: 0;
padding: 6px 13px;
}
table th:first-child,
table td:first-child {
margin-top: 0;
}
table th:last-child,
table td:last-child {
margin-bottom: 0;
}
.CodeMirror-lines {
padding-left: 4px;
}
.code-tooltip {
box-shadow: 0 1px 1px 0 rgba(0,28,36,.3);
border-top: 1px solid #eef2f2;
}
.md-fences,
code,
tt {
border: 1px solid #e7eaed;
background-color: #f8f8f8;
border-radius: 3px;
padding: 0;
padding: 2px 4px 0px 4px;
font-size: 0.9em;
}
code {
background-color: #f3f4f4;
padding: 0 2px 0 2px;
}
.md-fences {
margin-bottom: 15px;
margin-top: 15px;
padding-top: 8px;
padding-bottom: 6px;
}
.md-task-list-item > input {
margin-left: -1.3em;
}
@media print {
html {
font-size: 13px;
}
pre {
page-break-inside: avoid;
word-wrap: break-word;
}
}
.md-fences {
background-color: #f8f8f8;
}
#write pre.md-meta-block {
padding: 1rem;
font-size: 85%;
line-height: 1.45;
background-color: #f7f7f7;
border: 0;
border-radius: 3px;
color: #777777;
margin-top: 0 !important;
}
.mathjax-block>.code-tooltip {
bottom: .375rem;
}
.md-mathjax-midline {
background: #fafafa;
}
#write>h3.md-focus:before{
left: -1.5625rem;
top: .375rem;
}
#write>h4.md-focus:before{
left: -1.5625rem;
top: .285714286rem;
}
#write>h5.md-focus:before{
left: -1.5625rem;
top: .285714286rem;
}
#write>h6.md-focus:before{
left: -1.5625rem;
top: .285714286rem;
}
.md-image>.md-meta {
/*border: 1px solid #ddd;*/
border-radius: 3px;
padding: 2px 0px 0px 4px;
font-size: 0.9em;
color: inherit;
}
.md-tag {
color: #a7a7a7;
opacity: 1;
}
.md-toc {
margin-top:20px;
padding-bottom:20px;
}
.sidebar-tabs {
border-bottom: none;
}
#typora-quick-open {
border: 1px solid #ddd;
background-color: #f8f8f8;
}
#typora-quick-open-item {
background-color: #FAFAFA;
border-color: #FEFEFE #e5e5e5 #e5e5e5 #eee;
border-style: solid;
border-width: 1px;
}
/** focus mode */
.on-focus-mode blockquote {
border-left-color: rgba(85, 85, 85, 0.12);
}
header, .context-menu, .megamenu-content, footer{
font-family: "Segoe UI", "Arial", sans-serif;
}
.file-node-content:hover .file-node-icon,
.file-node-content:hover .file-node-open-state{
visibility: visible;
}
.mac-seamless-mode #typora-sidebar {
background-color: #fafafa;
background-color: var(--side-bar-bg-color);
}
.mac-os #write{
caret-color: AccentColor;
}
.md-lang {
color: #b4654d;
}
/*.html-for-mac {
--item-hover-bg-color: #E6F0FE;
}*/
#md-notification .btn {
border: 0;
}
.dropdown-menu .divider {
border-color: #e5e5e5;
opacity: 0.4;
}
.ty-preferences .window-content {
background-color: #fafafa;
}
.ty-preferences .nav-group-item.active {
color: white;
background: #999;
}
.menu-item-container a.menu-style-btn {
background-color: #f5f8fa;
background-image: linear-gradient( 180deg , hsla(0, 0%, 100%, 0.8), hsla(0, 0%, 100%, 0));
}
</style>
<style type='text/css' id="style-lp">ol, ul {padding-left: 40px}</style>
<title>lua-ffi</title>
</head>
<body class='typora-export os-windows'><div class='typora-export-content'>
<div id='write' class=''><h1 id='lua-ffi'><span>lua-ffi</span></h1><p><strong><span>lua-ffi</span></strong><span> is a portable and lightweight C Foreign Function Interface (FFI) extension for Lua. Based on libffi, it allows Lua scripts to call C functions and use C data types directly without the need to compile C wrapper code. It aims for high compatibility with the LuaJIT FFI syntax.</span></p><h2 id='features'><span>Features</span></h2><ul><li><p><strong><span>Portable:</span></strong><span> Compatible with Lua 5.x</span></p></li><li><p><strong><span>Lightweight:</span></strong><span> Written in pure C with a small footprint</span></p></li><li><p><strong><span>Dynamic:</span></strong><span> Declare C interfaces directly within Lua using </span><code>ffi.cdef</code></p></li></ul><h2 id='supported-c-data-types'><span>Supported C Data Types</span></h2><p><span>The integrated lexer recognizes a wide range of standard and system types natively. These can be used in declarations and memory allocations without additional setup.</span></p><figure class='table-figure'><table><thead><tr><th><span>Category</span></th><th><span>Supported Elements / Types</span></th></tr></thead><tbody><tr><td><span>Standard Base Types</span></td><td><code>void</code><span>, </span><code>bool</code><span>, </span><code>char</code><span>, </span><code>short</code><span>, </span><code>int</code><span>, </span><code>long</code><span>, </span><code>float</code><span>, </span><code>double</code></td></tr><tr><td><span>Fixed-width Integers</span></td><td><code>int8_t</code><span>, </span><code>int16_t</code><span>, </span><code>int32_t</code><span>, </span><code>int64_t</code><span>, </span><code>uint8_t</code><span>, </span><code>uint16_t</code><span>, </span><code>uint32_t</code><span>, </span><code>uint64_t</code></td></tr><tr><td><span>Qualifiers</span></td><td><code>const</code><span>, </span><code>signed</code><span>, </span><code>unsigned</code></td></tr><tr><td><span>Filesystem (POSIX)</span></td><td><code>ino_t</code><span>, </span><code>dev_t</code><span>, </span><code>mode_t</code><span>, </span><code>off_t</code><span>, </span><code>nlink_t</code><span>, </span><code>blksize_t</code><span>, </span><code>blkcnt_t</code></td></tr><tr><td><span>Process & Identity</span></td><td><code>pid_t</code><span>, </span><code>uid_t</code><span>, </span><code>gid_t</code></td></tr><tr><td><span>Memory & Time</span></td><td><code>size_t</code><span>, </span><code>ssize_t</code><span>, </span><code>time_t</code><span>, </span><code>useconds_t</code><span>, </span><code>suseconds_t</code></td></tr><tr><td><span>Complex Syntax</span></td><td><span>Pointers (</span><code>*</code><span>), Arrays (</span><code>[ ]</code><span>), </span><code>struct</code><span>, </span><code>union</code><span>, </span><code>typedef</code><span>, variadic functions (</span><code>...</code><span>)</span></td></tr></tbody></table></figure><h2 id='example'><span>Example</span></h2><p><span>This example demonstrates how to declare system functions, define structures, and allocate memory for C types.</span></p><pre class="md-fences md-end-block ty-contain-cm modeLoaded" spellcheck="false" lang="lua" style="break-inside: unset;"><div class="CodeMirror cm-s-inner cm-s-null-scroll CodeMirror-wrap" lang="lua"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 9.52344px; left: 8px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">local</span> <span class="cm-variable">ffi</span> = <span class="cm-builtin">require</span> <span class="cm-string">'ffi'</span></span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">local</span> <span class="cm-variable">path</span> = <span class="cm-builtin">require</span> <span class="cm-string">'pl.path'</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="" cm-zwsp="">
</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">local</span> <span class="cm-variable">is_windows</span> = <span class="cm-variable">path.is_windows</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="" cm-zwsp="">
</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">if</span> <span class="cm-variable">is_windows</span> <span class="cm-keyword">then</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-variable">ffi.cdef</span>(<span class="cm-string">[[</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">typedef struct {</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">uint32_t dwLowDateTime;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">uint32_t dwHighDateTime;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">} FILETIME;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="" cm-zwsp="">
</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">void GetSystemTimeAsFileTime(FILETIME *lpSystemTimeAsFileTime);</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">char *strerror(int errnum);</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">]]</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">else</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-variable">ffi.cdef</span>(<span class="cm-string">[[</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">struct timeval {</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">time_t tv_sec;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">suseconds_t tv_usec;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">};</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">int gettimeofday(struct timeval *tv, void *tz);</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">char *strerror(int errnum);</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">]]</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">end</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="" cm-zwsp="">
</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">if</span> <span class="cm-variable">is_windows</span> <span class="cm-keyword">then</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-keyword">local</span> <span class="cm-variable">ft</span> = <span class="cm-variable">ffi.new</span>(<span class="cm-string">'FILETIME'</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-variable">ffi.C.GetSystemTimeAsFileTime</span>(<span class="cm-variable">ft</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="" cm-zwsp="">
</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-comment">-- Convert cdata values to standard Lua numbers immediately.</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-comment">-- This avoids "arithmetic on a cdata value" errors.</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-keyword">local</span> <span class="cm-variable">h</span> = <span class="cm-builtin">tonumber</span>(<span class="cm-variable">ft.dwHighDateTime</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-keyword">local</span> <span class="cm-variable">l</span> = <span class="cm-builtin">tonumber</span>(<span class="cm-variable">ft.dwLowDateTime</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="" cm-zwsp="">
</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-comment">-- Calculation: (High << 32) + Low</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-keyword">local</span> <span class="cm-variable">ull</span> = (<span class="cm-variable">h</span> * <span class="cm-number">4294967296</span>) + <span class="cm-variable">l</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="" cm-zwsp="">
</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-comment">-- Convert to Unix Epoch (100-nanosecond intervals since 1601 to seconds since 1970)</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-keyword">local</span> <span class="cm-variable">unix_sec</span> = <span class="cm-builtin">math.floor</span>(<span class="cm-variable">ull</span> / <span class="cm-number">10000000</span> - <span class="cm-number">11644473600</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-keyword">local</span> <span class="cm-variable">unix_usec</span> = <span class="cm-builtin">math.floor</span>((<span class="cm-variable">ull</span> / <span class="cm-number">10</span>) % <span class="cm-number">1000000</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="" cm-zwsp="">
</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-builtin">print</span>(<span class="cm-string">'Windows System Time:'</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-builtin">print</span>(<span class="cm-string">'Seconds:'</span>, <span class="cm-variable">unix_sec</span>, <span class="cm-string">'Microseconds:'</span>, <span class="cm-variable">unix_usec</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">else</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-keyword">local</span> <span class="cm-variable">tv</span> = <span class="cm-variable">ffi.new</span>(<span class="cm-string">'struct timeval'</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-keyword">if</span> <span class="cm-variable">ffi.C.gettimeofday</span>(<span class="cm-variable">tv</span>, <span class="cm-keyword">nil</span>) < <span class="cm-number">0</span> <span class="cm-keyword">then</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-comment">-- ffi.errno() is also useful for error checking</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-builtin">print</span>(<span class="cm-string">'Error calling gettimeofday'</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-keyword">else</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-builtin">print</span>(<span class="cm-string">'POSIX System Time:'</span>)</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-builtin">print</span>(<span class="cm-string">'Seconds:'</span>, <span class="cm-builtin">tonumber</span>(<span class="cm-variable">tv.tv_sec</span>), <span class="cm-string">'Microseconds:'</span>, <span class="cm-builtin">tonumber</span>(<span class="cm-variable">tv.tv_usec</span>))</span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-keyword">end</span></span></pre><div class="" style="position: relative;"><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">end</span></span></pre></div></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 1245px;"></div><div class="CodeMirror-gutters" style="display: none; height: 1245px;"></div></div></div></pre><h2 id='lua-ffi-integration-guide'><span>Lua FFI Integration Guide</span></h2><p><span>This guide defines the standards for interfacing with external C functions and system APIs using the </span><strong><span>Foreign Function Interface (FFI)</span></strong><span>.</span></p><h3 id='declaration-of-c-structures-and-functions'><span>Declaration of C Structures and Functions</span></h3><p><span>Before an external function can be invoked, its signature must be declared via </span><code>ffi.cdef</code><span>.</span></p><ul><li><p><strong><span>Platform Guards:</span></strong><span> Use conditional logic to load platform-specific header definitions.</span></p></li><li><p><strong><span>Data Types:</span></strong><span> Use explicit bit-width types (e.g., </span><code>uint32_t</code><span>, </span><code>int64_t</code><span>) to ensure consistent memory layout across different architectures.</span></p></li></ul><pre class="md-fences md-end-block ty-contain-cm modeLoaded" spellcheck="false" lang="lua" style="break-inside: unset;"><div class="CodeMirror cm-s-inner cm-s-null-scroll CodeMirror-wrap" lang="lua"><div style="overflow: hidden; position: relative; width: 3px; height: 0px; top: 9.52344px; left: 8px;"><textarea autocorrect="off" autocapitalize="off" spellcheck="false" tabindex="0" style="position: absolute; bottom: -1em; padding: 0px; width: 1000px; height: 1em; outline: none;"></textarea></div><div class="CodeMirror-scrollbar-filler" cm-not-content="true"></div><div class="CodeMirror-gutter-filler" cm-not-content="true"></div><div class="CodeMirror-scroll" tabindex="-1"><div class="CodeMirror-sizer" style="margin-left: 0px; margin-bottom: 0px; border-right-width: 0px; padding-right: 0px; padding-bottom: 0px;"><div style="position: relative; top: 0px;"><div class="CodeMirror-lines" role="presentation"><div role="presentation" style="position: relative; outline: none;"><div class="CodeMirror-measure"><pre><span>xxxxxxxxxx</span></pre></div><div class="CodeMirror-measure"></div><div style="position: relative; z-index: 1;"></div><div class="CodeMirror-code" role="presentation" style=""><div class="CodeMirror-activeline" style="position: relative;"><div class="CodeMirror-activeline-background CodeMirror-linebackground"></div><div class="CodeMirror-gutter-background CodeMirror-activeline-gutter" style="left: 0px; width: 0px;"></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">local</span> <span class="cm-variable">ffi</span> = <span class="cm-builtin">require</span>(<span class="cm-string">'ffi'</span>)</span></pre></div><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span cm-text="" cm-zwsp="">
</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-comment">-- Defining structures and function prototypes</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">if</span> <span class="cm-variable">is_windows</span> <span class="cm-keyword">then</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-variable">ffi.cdef</span><span class="cm-string">[[</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">typedef struct {</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">uint32_t dwLowDateTime;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">uint32_t dwHighDateTime;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">} FILETIME;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">void GetSystemTimeAsFileTime(FILETIME *lpSystemTimeAsFileTime);</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">]]</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">else</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-variable">ffi.cdef</span><span class="cm-string">[[</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">struct timeval {</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">long tv_sec;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">long tv_usec;</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">};</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">int gettimeofday(struct timeval *tv, void *tz);</span></span></pre><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"> <span class="cm-string">]]</span></span></pre><div class="" style="position: relative;"><pre class=" CodeMirror-line " role="presentation"><span role="presentation" style="padding-right: 0.1px;"><span class="cm-keyword">end</span></span></pre></div></div></div></div></div></div><div style="position: absolute; height: 0px; width: 1px; border-bottom: 0px solid transparent; top: 461px;"></div><div class="CodeMirror-gutters" style="display: none; height: 461px;"></div></div></div></pre><h3 id='memory-allocation-ffinew'><span>Memory Allocation (</span><code>ffi.new</code><span>)</span></h3><p><span>Objects are created using </span><code>ffi.new</code><span>. These objects are managed by the automatic garbage collector.</span></p><ul><li><p><strong><span>Syntax:</span></strong><span> Use </span><code>ffi.new("type")</code><span> for single structures or </span><code>ffi.new("type[n]")</code><span> for arrays.</span></p></li><li><p><strong><span>Initialization:</span></strong><span> Memory is zero-initialized by default.</span></p></li></ul><h3 id='converting-c-data-to-lua-types'><span>Converting C Data to Lua Types</span></h3><p><span>Converting </span><code>cdata</code><span> (C data types) into native Lua numbers is essential to prevent "arithmetic on a cdata value" errors during calculations.</span></p><ul><li><p><strong><span>Explicit Casting:</span></strong><span> Use </span><code>tonumber()</code><span> to cast simple numeric types into Lua numbers.</span></p></li><li><p><strong><span>64-bit Calculations:</span></strong><span> When combining two 32-bit values (High/Low) into a single timestamp, use the formula </span><code>(high * 4294967296) + low</code><span>. This keeps the value within the precision limits of standard Lua doubles.</span></p></li></ul><h3 id='error-handling'><span>Error Handling</span></h3><p><span>FFI calls do not trigger native Lua errors automatically. Return values must be checked manually.</span></p><ul><li><p><strong><span>System Errors:</span></strong><span> Include </span><code>char *strerror(int errnum);</code><span> in your definitions to convert system error codes into human-readable strings.</span></p></li><li><p><strong><span>Validation:</span></strong><span> Check return codes (e.g., values </span><code>< 0</code><span>) immediately following the function call.</span></p></li></ul><h3 id='best-practices'><span>Best Practices</span></h3><ul><li><p><strong><span>Static Scope:</span></strong><span> Call </span><code>ffi.cdef</code><span> once at the module level. Avoid re-defining signatures inside loops or functions.</span></p></li><li><p><strong><span>Performance:</span></strong><span> Direct field access (e.g., </span><code>struct.member</code><span>) is highly optimized and should be preferred over complex abstraction layers.</span></p></li></ul><h2 id='acknowledgements'><span>Acknowledgements</span></h2><p><span>This project was inspired by and takes concepts from the following repositories:</span></p><ul><li><p><a href='https://github.com/q66/cffi-lua'><span>cffi-lua</span></a></p></li><li><p><a href='https://luajit.org/ext_ffi.html'><span>LuaJIT FFI</span></a></p></li></ul><p><span>Special thanks to the authors for their excellent work in the Lua ecosystem.</span></p><h2 id='license'><span>License</span></h2><p><span>See </span><code>https://github.com/OneLuaPro/lua-ffi/blob/main/LICENSE</code><span>.</span></p></div></div>
</body>
</html>