{"id":303,"date":"2016-07-14T15:12:16","date_gmt":"2016-07-14T07:12:16","guid":{"rendered":"http:\/\/www.5x44.cn\/?p=303"},"modified":"2016-07-14T22:06:33","modified_gmt":"2016-07-14T14:06:33","slug":"%e5%86%85%e5%ad%98%e5%88%86%e9%85%8d","status":"publish","type":"post","link":"https:\/\/www.5x44.cn\/?p=303","title":{"rendered":"\u5185\u5b58\u5206\u914d"},"content":{"rendered":"

ISO C\u6307\u5b9a\u4e86\u4e09\u4e2a\u51fd\u6570\u7528\u4e8e\u5185\u5b58\u5206\u914d\uff1a<\/p>\n

    \n
  1. malloc<\/span>\uff0c\u5b83\u5206\u914d\u6307\u5b9a\u5b57\u8282\u6570\u7684\u5185\u5b58\u7a7a\u95f4\u3002\u88ab\u5206\u914d\u7684\u5185\u5b58\u7a7a\u95f4\u521d\u59cb\u503c\u662f\u968f\u673a\u3002<\/li>\n
  2. calloc<\/span>\uff0c\u5b83\u5206\u914d\u6307\u5b9a\u5bf9\u8c61\u6570\u7684\u5185\u5b58\u7a7a\u95f4\u3002\u7a7a\u95f4\u88ab\u521d\u59cb\u5316\u62100\u3002<\/li>\n
  3. realloc<\/span>\uff0c\u5b83\u53ef\u4ee5\u589e\u52a0\u6216\u51cf\u5c11\u4e4b\u524d\u5206\u914d\u7a7a\u95f4\u7684\u5927\u5c0f\u3002\u5f53\u7a7a\u95f4\u589e\u957f\uff0c\u5b83\u4f1a\u628a\u4e4b\u524d\u5206\u914d\u7684\u7a7a\u95f4\u79fb\u52a8\u5230\u62e5\u6709\u5927\u7684\u5730\u65b9\u518d\u52a0\u4e0a\u589e\u957f\u7684\u7a7a\u95f4\u505a\u4e3a\u7ed3\u5c3e\u3002\u540c\u65f6\uff0c\u65b0\u589e\u52a0\u7a7a\u95f4\u7684\u521d\u59cb\u503c\u662f\u4e0d\u786e\u5b9a\u7684\u3002<\/li>\n<\/ol>\n

    #include <stdlib.h><\/span><\/p>\n

    void *malloc(size_t size<\/em>);<\/span><\/p>\n

    void *calloc(size_t nobj<\/em>, size_t size<\/em>);<\/span><\/p>\n

    void *realloc(void *ptr<\/em>, size_t newsize<\/em>);<\/span><\/p>\n

    \u4e0a\u9762\u4e09\u4e2a\u51fd\u6570\u8fd4\u56de\u7684\u6307\u9488\u786e\u4fdd\u62e5\u6709\u5408\u9002\u7684\u5bf9\u9f50\uff0c\u53ef\u4ee5\u5b58\u50a8\u4efb\u610f\u7c7b\u578b\u7684\u5bf9\u8c61\u3002\u4f8b\u5982\uff0c\u591a\u6570\u7cfb\u7edf\u8981\u6c42double<\/span>\u7c7b\u578b\u6570\u636e\u8981\u5b58\u50a8\u5728\u5185\u5b58\u7684\u4f4d\u7f6e\u662f8\u7684\u500d\u6570\u7684\u4f4d\u7f6e\uff0c\u800c\u901a\u8fc7\u8fd9\u4e09\u4e2a\u51fd\u6570\u8fd4\u56de\u7684\u6307\u9488\u5df2\u7ecf\u662f\u5bf9\u9f50\u7684\u3002
    \nvoid free(void *ptr);<\/span>
    \n\u51fd\u6570free\u53ef\u4ee5\u91ca\u653eptr<\/em><\/span>\u6307\u5411\u7684\u5185\u5b58\u7a7a\u95f4\uff0c\u88ab\u91ca\u653e\u7684\u5185\u5b58\u4f1a\u653e\u5230\u4e00\u4e2a\u53ef\u7528\u5185\u5b58\u6c60\u4e2d\uff0c\u7528\u4e8e\u4ee5\u540e\u5185\u5b58\u5206\u914d\u3002<\/p>\n

    realloc<\/span>\u51fd\u6570\u53ef\u4ee5\u8ba9\u6211\u4eec\u589e\u52a0\u6216\u51cf\u5c11\u4e4b\u524d\u5206\u914d\u7a7a\u95f4\u7684\u5927\u5c0f\uff08\u591a\u6570\u7528\u6765\u589e\u52a0\uff09\u3002\u4f8b\u5982\uff0c\u6211\u4eec\u5206\u914d\u4e86\u4e00\u6bb5\u7a7a\u95f4\u53ef\u4ee5\u5728\u8fd0\u884c\u65f6\u5b58\u50a8512\u4e2a\u5143\u7d20\uff0c\u4f46\u5728\u5b9e\u9645\u4f7f\u7528\u8fc7\u7a0b\u4e2d\u53d1\u73b0\u4e0d\u591f\uff0c\u8fd9\u65f6\u5c31\u53ef\u4ee5\u4f7f\u7528realloc\u91cd\u65b0\u5206\u914d\u7a7a\u95f4\u3002\u5982\u679c\u5728\u8be5\u5b58\u50a8\u533a\u540e\u6709\u8db3\u591f\u7684\u7a7a\u95f4\u53ef\u4f9b\u6269\u5145\uff0c\u5219\u53ef\u5728\u539f\u5b58\u50a8\u533a\u540e\u9762\u589e\u52a0\u7a7a\u95f4\uff0c\u65e0\u9700\u79fb\u52a8\u6570\u636e\uff0c\u5e76\u8fd4\u56de\u539f\u6765\u7684\u6307\u9488\u503c\u3002\u5982\u679c\u5728\u539f\u5b58\u50a8\u533a\u540e\u6ca1\u6709\u8db3\u591f\u7684\u7a7a\u95f4\uff0c\u5219realloc\u5206\u914d\u4e00\u4e2a\u8db3\u591f\u5927\u7684\u5b58\u50a8\u533a\uff0c\u5c06\u73b0\u6709\u6570\u636e\u79fb\u52a8\u5230\u65b0\u5206\u914d\u7684\u5730\u5740\uff0c\u7136\u540e\u91ca\u653e\u539f\u6709\u5730\u5740\u7a7a\u95f4\uff0c\u5e76\u8fd4\u56de\u65b0\u5730\u5740\u7684\u6307\u9488\u3002<\/p>\n

    \u6ce8\uff1a<\/span>\u5982\u679crealloc\u7684\u53c2\u6570ptr\u662fnull\uff0c\u90a3\u4e48\u5b83\u7684\u884c\u4e3a\u548cmalloc\u51fd\u6570\u4e00\u6837\u3002<\/span><\/p>\n

    \u5206\u914d\u5185\u5b58\u7684\u4f8b\u7a0b\u901a\u5e38\u662f\u7528sbrk<\/span>\u7cfb\u7edf\u8c03\u7528\u5b9e\u73b0\u3002\u8fd9\u4e2a\u7cfb\u7edf\u8c03\u7528\u6269\u5c55\uff08\u6216\u7f29\u5c0f\uff09\u4e86\u8fdb\u7a0b\u7684\u5806\u3002<\/p>\n

    \u867d\u7136sbrk<\/span>\u53ef\u4ee5\u6269\u5c55\u6216\u51cf\u5c11\u8fdb\u7a0b\u7684\u5185\u5b58\uff0c\u4f46\u591a\u6570malloc<\/span>\u548cfree<\/span>\u7684\u7248\u672c\u90fd\u4e0d\u80fd\u51cf\u5c11\u5b83\u4eec\u7684\u5185\u5b58\u3002free<\/span>\u91ca\u653e\u5185\u5b58\u540e\u53ef\u4ee5\u518d\u6b21\u4f7f\u7528\u5b83\u4eec\uff0c\u4f46\u662f\u88abfree<\/span>\u7684\u5185\u5b58\u6ca1\u6709\u8fd4\u56de\u5230\u5185\u6838\uff0c\u800c\u662f\u7559\u5728malloc\u6c60\u4e2d\u3002<\/p>\n

    \u591a\u6570\u7684\u5b9e\u73b0\u4f1a\u5206\u914d\u6bd4\u9700\u6c42\u591a\u4e00\u70b9\u7684\u5185\u5b58\uff0c\u7528\u8fd9\u4e9b\u989d\u5916\u7684\u5185\u5b58\u8bb0\u5f55\u5206\u914d\u5757\u7684\u5927\u5c0f\u3001 \u6307\u5411\u4e0b\u4e00\u4e2a\u5757\u7684\u6307\u9488\uff0c\u7b49\u7b49\u3002\u8fd9\u610f\u5473\u7740\u5728\u5206\u914d\u5757\u4e2d\u8d85\u91cf\u5199\u5165\u4f1a\u8986\u76d6\u4e0b\u4e00\u4e2a\u5757\u7684\u4fdd\u5b58\u4fe1\u606f\u3002\u8fd9\u79cd\u7c7b\u578b\u7684\u9519\u8bef\u90fd\u662f\u707e\u96be\u6027\u7684\uff0c\u800c\u4e14\u5f88\u96be\u88ab\u53d1\u73b0\uff0c\u56e0\u4e3a\u8fd9\u79cd\u9519\u8bef\u90fd\u662f\u5728\u7a0b\u5e8f\u8fd0\u884c\u5f88\u4e45\u4ee5\u540e\u624d\u4f1a\u51fa\u73b0\u3002\u5982\u679c\u5728\u5f53\u524d\u5206\u914d\u5757\u7684\u5f00\u5934\u4e4b\u524d\u8fdb\u884c\u8986\u76d6\u5199\u5165\uff0c\u4e5f\u4f1a\u8986\u76d6\u5f53\u524d\u5757\u7684\u4fdd\u5b58\u4fe1\u606f\u3002<\/p>\n

    \u8986\u76d6\u52a8\u6001\u5206\u914d\u5185\u5b58\u5757\u7684\u5f00\u5934\u4e4b\u524d\u6216\u7ed3\u5c3e\u4e4b\u540e\u7684\u4fe1\u606f\u4e0d\u4ec5\u4ec5\u7834\u574f\u4e86\u5185\u90e8\u4fdd\u5b58\u4fe1\u606f\u3002\u4e00\u4e2a\u52a8\u6001\u5206\u914d\u7684\u5185\u5b58\u5757\u4e4b\u524d\u548c\u4e4b\u540e\u80fd\u88ab\u5176\u5b83\u52a8\u592a\u5206\u914d\u7684\u5bf9\u8c61\u9690\u5f0f\u4f7f\u7528\u3002\u8fd9\u4e9b\u5bf9\u8c61\u5f88\u6709\u53ef\u80fd\u548c\u7834\u574f\u5b83\u4eec\u7684\u4ee3\u7801\u65e0\u5173\uff0c\u8fd9\u4f7f\u5f97\u627e\u5230\u7834\u574f\u6e90\u975e\u5e38\u56f0\u96be\u3002<\/p>\n

    \u5176\u5b83\u975e\u5e38\u81f4\u547d\u7684\u9519\u8bef<\/span>\u5305\u62ec\u4f7f\u7528free<\/span>\u91ca\u653e\u4e00\u4e2a\u5df2\u7ecf\u91ca\u653e\u8fc7\u7684\u5185\u5b58\u5757\u3001\u4f7f\u7528free<\/span>\u91ca\u653e\u4e00\u4e2a\u4e0d\u662f\u4f7f\u7528alloc<\/span>\u51fd\u6570\u83b7\u5f97\u7684\u5185\u5b58\u5757\u3002\u5982\u679c\u8fdb\u7a0b\u8bbe\u7528malloc\u540e\u5fd8\u8bb0\u4f7f\u7528free\u91ca\u653e\u5185\u5b58\uff0c\u90a3\u4e48\u8fdb\u7a0b\u7684\u5185\u5b58\u4f1a\u6301\u7eed\u589e\u957f\uff0c\u8fd9\u88ab\u79f0\u4f5c\u2014\u2014\u5185\u5b58\u6cc4\u9732\u3002\u5f53\u8d85\u51fa\u9875\u9762\u6587\u4ef6\u65f6\u6548\u7387\u4f1a\u964d\u4f4e\u3002<\/p>\n

    \u56e0\u4e3a\u5185\u5b58\u5206\u914d\u7684\u9519\u8bef\u5f88\u96be\u8ddf\u8e2a\uff0c\u4e00\u4e9b\u7cfb\u7edf\u63d0\u4f9b\u4e86\u989d\u5916\u7684\u7248\u672c\uff0c\u6bcf\u6b21\u6267\u884c\u5185\u5b58\u5206\u914d\u6216\u91ca\u653e\u5185\u5b58\u65f6\uff0c\u90fd\u4f1a\u8fdb\u884c\u68c0\u67e5\u3002<\/p>\n

    \u5176\u5b83\u7684\u5185\u5b58\u5206\u914d\u51fd\u6570<\/strong><\/h2>\n

    libmalloc<\/span><\/p>\n

    \u57fa\u4e8eSVR4\u7684\u7cfb\u7edf\uff0c\u5982\uff0cSolaris\uff0c\u5305\u542blibmalloc\u5e93\uff0c\u5b83\u63d0\u4f9b\u4e86\u4e00\u7ec4\u5339\u914dISO C\u7684\u5185\u5b58\u5206\u914d\u51fd\u6570\u3002libmalloc\u5e93\u5305\u542bmallopt<\/span>\uff0c\u4e00\u4e2a\u5141\u8bb8\u8fdb\u7a0b\u8bbe\u7f6e\u53ef\u4ee5\u63a7\u5236\u5b58\u50a8\u5206\u914d\u5668\u64cd\u4f5c\u7684\u53d8\u91cf\u3002\u4e00\u4e2a\u51fd\u6570\u8c03\u7528mallinfo\u53ef\u4ee5\u63d0\u4f9b\u5185\u5b58\u5206\u914d\u5668\u7684\u72b6\u6001\u3002<\/p>\n

    vmalloc<\/span><\/p>\n

    Vo\u63cf\u8ff0\u4e86\u4e00\u79cd\u5185\u5b58\u5206\u914d\u5668\uff0c\u5b83\u5141\u8bb8\u8fdb\u7a0b\u5206\u914d\u5185\u5b58\u65f6\uff0c\u5bf9\u4e0d\u540c\u533a\u57df\u7684\u5185\u5b58\u4f7f\u7528\u4e0d\u540c\u7684\u6280\u672f\u3002\u9664\u4e86vmalloc\u7279\u6709\u7684\u51fd\u6570\uff0c\u8be5\u5e93\u540c\u6837\u63d0\u4f9b\u4e86ISO C\u5185\u5b58\u5206\u914d\u529f\u80fd\u3002<\/p>\n

    quick-fit<\/span><\/p>\n

    \u4ece\u5386\u53f2\u4e0a\u770b\uff0c\u6807\u51c6malloc\u7b97\u6cd5\u8981\u4e48\u4f7f\u7528best-fit\u7b56\u7565\uff0c\u8981\u4e48\u4f7f\u7528first-fit\u7b56\u7565\u3002quick-fit\u662f\u6bd4\u524d\u4e24\u8005\u90fd\u5feb\uff0c\u4f46\u662f\u4f1a\u7528\u66f4\u591a\u7684\u5185\u5b58\u3002\u8fd9\u4e2a\u7b97\u6cd5\u662f\u57fa\u4e8e\u5c06\u5185\u5b58\u5206\u5272\u6210\u591a\u4e2a\u4e0d\u540c\u5927\u5c0f\u7684\u7f13\u5b58\u5757\u5e76\u7ef4\u62a4\u4e0d\u4f7f\u7528\u7684\u7f13\u5b58\u3002<\/p>\n

    alloca<\/span>\u51fd\u6570<\/p>\n

    \u53e6\u5916\u4e00\u4e2a\u503c\u5f97\u4e00\u63d0\u7684\u51fd\u6570\u2014\u2014alloca\u3002alloca\u4f7f\u7528\u65b9\u6cd5\u548cmalloc\u4e00\u6837\uff1b\u4f46\u662f\u5b83\u5206\u914d\u7684\u5185\u5b58\u5e76\u4e0d\u662f\u4ece\u5806\u4e2d\u5206\u914d\uff0c\u800c\u662f\u5728\u6808\u4e2d\u5206\u914d\u3002\u5b83\u7684\u4f18\u70b9\u662f\u4e0d\u7528\u624b\u52a8\u7684\u91ca\u653e\u5185\u5b58\uff0c\u5f53\u7a0b\u5e8f\u8fd4\u56de\u65f6\u4f1a\u81ea\u52a8\u91ca\u653e\u5206\u914d\u7684\u5185\u5b58\u3002\u7f3a\u70b9\u662f\u5f88\u591a\u7cfb\u7edf\u4e0d\u652f\u6301\u8fd9\u4e2a\u51fd\u6570\u3002<\/p>\n

    PS:LINUX\u652f\u6301alloca<\/p>\n","protected":false},"excerpt":{"rendered":"

    ISO C\u6307\u5b9a\u4e86\u4e09\u4e2a\u51fd\u6570\u7528\u4e8e\u5185\u5b58\u5206\u914d\uff1a malloc\uff0c\u5b83\u5206\u914d\u6307\u5b9a\u5b57\u8282\u6570\u7684\u5185\u5b58\u7a7a\u95f4\u3002\u88ab\u5206\u914d\u7684\u5185\u5b58\u7a7a\u95f4\u521d\u59cb\u503c\u662f\u968f\u673a\u3002 calloc\uff0c\u5b83\u5206\u914d\u6307\u5b9a\u5bf9\u8c61\u6570\u7684\u5185\u5b58\u7a7a\u95f4\u3002\u7a7a\u95f4…<\/p>\n

    Read More Read More<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[18],"tags":[],"class_list":["post-303","post","type-post","status-publish","format-standard","hentry","category-apue"],"_links":{"self":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts\/303","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=303"}],"version-history":[{"count":16,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts\/303\/revisions"}],"predecessor-version":[{"id":320,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts\/303\/revisions\/320"}],"wp:attachment":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=303"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=303"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=303"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}