{"id":1289,"date":"2024-09-19T19:13:52","date_gmt":"2024-09-19T11:13:52","guid":{"rendered":"https:\/\/www.madbull.site\/?p=1289"},"modified":"2024-09-19T23:09:18","modified_gmt":"2024-09-19T15:09:18","slug":"%e6%97%a0%e9%94%81%e7%bc%96%e7%a8%8b-c%e8%af%ad%e8%a8%80","status":"publish","type":"post","link":"https:\/\/www.madbull.site\/?p=1289","title":{"rendered":"\u65e0\u9501\u7f16\u7a0b–C\u8bed\u8a00"},"content":{"rendered":"\n

\u9501\u5e26\u6765\u7684\u5f00\u9500\u662f\u6bd4\u8f83\u5927\u7684\uff0c\u5bf9\u4e8e\u9ad8\u5e76\u53d1\u5904\u7406\u7684\u6570\u636e\uff0c\u4f7f\u7528\u4e00\u4e9b\u539f\u5b50\u64cd\u4f5c\u51fd\u6570\uff0c\u53ef\u4ee5\u6709\u6548\u907f\u514d\u4e0a\u9501\u7684\u5f00\u9500\u3002<\/p>\n\n\n\n

GCC\u5185\u7f6e\u4e86\u4e00\u4e9b\u539f\u5b50\u64cd\u4f5c\u51fd\u6570\uff0c\u53ef\u4ee5\u7528\u6765\u652f\u6301\u65e0\u9501\u7f16\u7a0b\uff0c\u7528\u4f2a\u4ee3\u7801\u6bd4\u8f83\u597d\u7406\u89e3\u8fd9\u4e9b\u51fd\u6570\u7684\u5177\u4f53\u5904\u7406\u65b9\u5f0f\u3002<\/p>\n\n\n\n

\u91cd\u70b9\u662f\uff1a\u8fd9\u4e9b\u90fd\u662f\u539f\u5b50\u64cd\u4f5c\uff0c\u662f\u7ebf\u7a0b\u5b89\u5168\u7684<\/mark><\/strong>\u3002<\/p>\n\n\n\n

<\/div>\n\n\n\n

\u5e38\u7528\u6765\u5b9e\u73b0\u65e0\u9501\u7f16\u7a0b\u7684\u51fd\u6570\u6709\uff1a<\/p>\n\n\n\n

<\/div>\n\n\n\n

1\u3001\u81ea\u589e\u5e76\u8fd4\u56de\u539f\u503c<\/strong><\/p>\n\n\n\n

<\/div>\n\n\n\n

type __sync_fetch_and_add(type * ptr, type value)<\/code><\/p>\n\n\n\n

\u89e3\u91ca\uff1a*ptr \u7684\u503c\u52a0\u4e0a value \u7684\u503c\uff0c\u7136\u540e\u8d4b\u503c\u7ed9 *ptr\uff0c\u5e76\u8fd4\u56de *ptr \u539f\u6765\u7684\u503c\u3002<\/p>\n\n\n\n

<\/div>\n\n\n\n

\u4f2a\u4ee3\u7801\u89e3\u91ca\uff1a<\/p>\n\n\n\n

<\/div>\n\n\n\n
type old_value = *ptr ;\n*ptr += value ;\nreturn old_value ;<\/code><\/pre>\n\n\n\n
<\/div>\n\n\n\n
2\u3001\u81ea\u589e\u5e76\u8fd4\u56de\u65b0\u503c<\/strong><\/p>\n\n\n\n
<\/div>\n\n\n\n
type __sync_add_and_fetch(type * ptr, type value)<\/code><\/p>\n\n\n\n
\u89e3\u91ca\uff1a*ptr \u7684\u503c\u52a0\u4e0a value \u7684\u503c\uff0c\u7136\u540e\u8d4b\u503c\u7ed9 *ptr\uff0c\u5e76\u8fd4\u56de *ptr \u7684\u65b0\u503c\u3002<\/p>\n\n\n\n
<\/div>\n\n\n\n
\u4f2a\u4ee3\u7801\u89e3\u91ca\uff1a<\/p>\n\n\n\n
<\/div>\n\n\n\n
*ptr += value ;\nreturn *ptr ;<\/code><\/pre>\n\n\n\n
<\/div>\n\n\n\n
3\u3001\u81ea\u51cf\u5e76\u8fd4\u56de\u539f\u503c<\/strong><\/p>\n\n\n\n
<\/div>\n\n\n\n
type __sync_fetch_and_sub(type * ptr, type value)<\/code><\/p>\n\n\n\n
\u89e3\u91ca\uff1a*ptr \u7684\u503c\u51cf\u53bb value \u7684\u503c\uff0c\u7136\u540e\u8d4b\u503c\u7ed9 *ptr\uff0c\u5e76\u8fd4\u56de *ptr \u539f\u6765\u7684\u503c\u3002\u548c\u7b2c 1 \u4e2a\u7c7b\u4f3c\u3002<\/p>\n\n\n\n
<\/div>\n\n\n\n
4\u3001\u81ea\u51cf\u5e76\u8fd4\u56de\u65b0\u503c<\/strong><\/p>\n\n\n\n
<\/div>\n\n\n\n
type __sync_sub_and_fetch(type * ptr, type value)<\/code><\/p>\n\n\n\n
\u89e3\u91ca\uff1a*ptr \u7684\u503c\u51cf\u53bb value \u7684\u503c\uff0c\u7136\u540e\u8d4b\u503c\u7ed9 *ptr\uff0c\u5e76\u8fd4\u56de *ptr \u7684\u65b0\u503c\u3002\u548c\u7b2c 2 \u4e2a\u7c7b\u4f3c\u3002<\/p>\n\n\n\n
<\/div>\n\n\n\n
5\u3001\u6bd4\u8f83\u5e76\u4ea4\u6362\u6570\u636e\uff0c\u5e76\u8fd4\u56de\u662f\u5426\u6210\u529f\u3002<\/strong><\/p>\n\n\n\n
<\/div>\n\n\n\n
int __sync_bool_compare_and_swap(type * ptr, type oldval, type newval)<\/code><\/p>\n\n\n\n
\u89e3\u91ca\uff1a\u5982\u679c *ptr \u548c oldval \u7684\u503c\u76f8\u7b49\uff0c\u5219\u628a newval \u8d4b\u503c\u7ed9 *ptr\u3002\u5982\u679c\u5bf9\u6bd4\u6210\u529f\uff0c\u8fd4\u56de1\uff1b\u5931\u8d25\uff0c\u5219\u8fd4\u56de0 \u3002<\/p>\n\n\n\n
<\/div>\n\n\n\n
\u7528\u4f2a\u4ee3\u7801\u89e3\u91ca\uff1a<\/p>\n\n\n\n
<\/div>\n\n\n\n
if( *ptr == oldval ) {\n    *ptr = newval ;\n    return 1 ;\n} else return 0 ;<\/code><\/pre>\n\n\n\n
<\/div>\n\n\n\n
6\u3001\u6bd4\u8f83\u5e76\u4ea4\u6362\u6570\u636e\uff0c\u5e76\u8fd4\u56de\u5bf9\u5e94\u503c\u3002<\/strong><\/p>\n\n\n\n
<\/div>\n\n\n\n
int __sync_val_compare_and_swap(type * ptr, type oldval, type newval)<\/code><\/p>\n\n\n\n
\u89e3\u91ca\uff1a\u5982\u679c *ptr \u548c oldval \u7684\u503c\u76f8\u7b49\uff0c\u5219\u628a newval \u8d4b\u503c\u7ed9 *ptr \u3002\u5173\u952e\u70b9\uff1a\u5bf9\u6bd4\u6210\u529f\u548c\u5931\u8d25\u8fd4\u56de\u7684\u503c\u662f\u4e0d\u4e00\u6837\u7684\uff1a<\/p>\n\n\n\n
\u6210\u529f\uff0c\u5219\u8fd4\u56de\u65e7\u503c oldval<\/p>\n\n\n\n
\u5931\u8d25\uff0c\u5219\u8fd4\u56de\u539f\u503c *ptr<\/p>\n\n\n\n
<\/div>\n\n\n\n
\u7528\u4f2a\u4ee3\u7801\u89e3\u91ca\uff1a<\/p>\n\n\n\n
<\/div>\n\n\n\n
if( *ptr == oldval ) {\n    *ptr = newval ;\n    return oldval ;\n} else return *ptr ;<\/code><\/pre>\n\n\n\n
<\/div>\n\n\n\n
\u5b8f\u4ee3\u7801<\/strong><\/p>\n\n\n\n
<\/div>\n\n\n\n
\u4e3a\u4e86\u65b9\u4fbf\u4f7f\u7528\uff0c\u5f80\u5f80\u4f1a\u4f7f\u7528\u5b8f\u4ee3\u7801\u5bf9\u8fd96\u4e2a\u51fd\u6570\u8fdb\u7a0b\u5904\u7406\u3002\u901a\u5e38\u7684\u5199\u6cd5\u5982\u4e0b\uff1a<\/p>\n\n\n\n
<\/div>\n\n\n\n
#define ATOMIC_READ(_v) __sync_fetch_and_add(&(_v), 0)\n#define ATOMIC_INCREMENT(_v) (void)__sync_fetch_and_add(&(_v), 1)\n#define ATOMIC_DECREMENT(_v) (void)__sync_fetch_and_sub(&(_v), 1)\n#define ATOMIC_INCREASE(_v, _n) __sync_add_and_fetch(&(_v), (_n))\n#define ATOMIC_DECREASE(_v, _n) __sync_sub_and_fetch(&(_v), (_n))\n#define ATOMIC_CAS(_v, _o, _n) __sync_bool_compare_and_swap(&(_v), (_o), (_n))\n#define ATOMIC_CAS_RETURN(_v, _o, _n) __sync_val_compare_and_swap(&(_v), (_o), (_n))\n\n#define ATOMIC_SET(_v, _n) {\\\n    int _b = 0;\\\n    do {\\\n        _b = ATOMIC_CAS(_v, ATOMIC_READ(_v), _n);\\\n    } while (__builtin_expect(!_b, 0));\\\n}\n\n#define ATOMIC_SET_IF(_v, _c, _n, _t) {\\\n    _t _o = ATOMIC_READ(_v);\\\n    while (__builtin_expect((_o _c (_n)) && !ATOMIC_CAS(_v, _o, _n), 0)) \\\n        _o = ATOMIC_READ(_v);\\\n}<\/code><\/pre>\n\n\n\n
<\/div>\n\n\n\n
\u6587\u7ae0\uff1ahttps:\/\/www.madbull.site\/?p=897<\/a> \u7684libhl\u5e93\u91cc\uff0c\u6709\u76f8\u5173\u7528\u6cd5\uff0c\u53ef\u4e0b\u8f7d\u6e90\u4ee3\u7801\u5206\u6790\u3002\u53c2\u8003\u6e90\u7801\u4e2d src\/atomic_defs.h \u5934\u6587\u4ef6\u7684\u5b9a\u4e49\u4ee5\u53ca\u5728\u6b64\u9879\u76ee\u91cc\u7684\u5177\u4f53\u7528\u6cd5\u3002<\/p>\n\n\n\n
\u4e5f\u53ef\u4ee5\u76f4\u63a5\u8bbf\u95ee github \u6e90\u4ee3\u7801\uff1ahttps:\/\/github.com\/xant\/libhl\/blob\/master\/src\/atomic_defs.h<\/a><\/p>\n\n\n\n
<\/div>\n\n\n\n
\n\n\n\n
<\/div>\n\n\n\n
\u4ee5\u540e\u6709\u65f6\u95f4\u518d\u8be6\u7ec6\u89e3\u6790\u4f7f\u7528\u65b9\u6cd5\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u9501\u5e26\u6765\u7684\u5f00\u9500\u662f\u6bd4\u8f83\u5927\u7684\uff0c\u5bf9\u4e8e\u9ad8\u5e76\u53d1\u5904\u7406\u7684\u6570\u636e\uff0c\u4f7f\u7528\u4e00\u4e9b\u539f\u5b50\u64cd\u4f5c\u51fd\u6570\uff0c\u53ef\u4ee5\u6709\u6548\u907f\u514d\u4e0a\u9501\u7684\u5f00\u9500\u3002
\nGCC\u5185\u7f6e\u4e86\u4e00\u4e9b\u539f\u5b50\u64cd\u4f5c\u51fd\u6570\u3002\u91cd\u70b9\u662f\uff1a\u8fd9\u4e9b\u90fd\u662f\u539f\u5b50\u64cd\u4f5c\uff0c\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\u3002
\n\u5e38\u7528\u6765\u5b9e\u73b0\u65e0\u9501\u7f16\u7a0b\u7684\u51fd\u6570\u6709\uff1a
\n1\u3001\u81ea\u589e\u5e76\u8fd4\u56de\u539f\u503c
\ntype __sync_fetch_and_add(type * ptr, type value)
\n\u89e3\u91ca\uff1a*ptr \u7684\u503c\u52a0\u4e0a value \u7684\u503c\uff0c\u7136\u540e\u8d4b\u503c\u7ed9 *ptr\uff0c\u5e76\u8fd4\u56de *ptr \u539f\u6765\u7684\u503c\u3002
\n\u7528\u4f2a\u4ee3\u7801\u89e3\u91ca\uff1a
\nold_value = *ptr ;
\n*ptr += value ;
\nreturn old_value ;<\/p>\n","protected":false},"author":1,"featured_media":559,"comment_status":"open","ping_status":"open","sticky":false,"template":"single-with-sidebar","format":"standard","meta":{"footnotes":""},"categories":[156,135,154],"tags":[466,468,467,465],"class_list":["post-1289","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-c-c","category-linux","category-154","tag-__sync","tag-automic","tag-swap","tag-465"],"_links":{"self":[{"href":"https:\/\/www.madbull.site\/index.php?rest_route=\/wp\/v2\/posts\/1289","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.madbull.site\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.madbull.site\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.madbull.site\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.madbull.site\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1289"}],"version-history":[{"count":13,"href":"https:\/\/www.madbull.site\/index.php?rest_route=\/wp\/v2\/posts\/1289\/revisions"}],"predecessor-version":[{"id":1306,"href":"https:\/\/www.madbull.site\/index.php?rest_route=\/wp\/v2\/posts\/1289\/revisions\/1306"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.madbull.site\/index.php?rest_route=\/wp\/v2\/media\/559"}],"wp:attachment":[{"href":"https:\/\/www.madbull.site\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1289"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.madbull.site\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1289"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.madbull.site\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1289"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}