{"id":690,"date":"2017-02-15T16:42:07","date_gmt":"2017-02-15T08:42:07","guid":{"rendered":"http:\/\/www.5x44.cn\/?p=690"},"modified":"2017-02-15T16:42:07","modified_gmt":"2017-02-15T08:42:07","slug":"sigsetjmp%e5%92%8csiglongjmp%e5%87%bd%e6%95%b0","status":"publish","type":"post","link":"https:\/\/www.5x44.cn\/?p=690","title":{"rendered":"sigsetjmp\u548csiglongjmp\u51fd\u6570"},"content":{"rendered":"

\u5728APUE 7.10\u8282\uff0c\u6211\u4eec\u63cf\u8ff0\u8fc7setjmp\u548clongjmp\u51fd\u6570\uff0c\u5b83\u66fe\u88ab\u7528\u4e8e\u975e\u672c\u5730\u5206\u652f\u8df3\u8f6c\u3002longjmp\u51fd\u6570\u5e38\u88ab\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u8c03\u7528\uff0c\u7528\u4e8e\u8fd4\u56de\u7a0b\u5e8f\u7684\u4e3b\u5faa\u73af\uff0c\u800c\u4e0d\u662f\u8fd4\u56de\u5230\u53e5\u67c4\uff08handler\uff09\u3002\u6211\u4eec\u5df2\u7ecf\u5728FIGURE10.8\u548c10.11\u89c1\u8fc7\u4e86\u3002<\/p>\n

\u5728\u8c03\u7528longjmp<\/span>\u8fc7\u7a0b\u4e2d\u6709\u4e2a\u95ee\u9898\u3002\u5f53\u4fe1\u53f7\u88ab\u6355\u83b7\u65f6\uff0c\u4f7f\u7528\u8be5\u4fe1\u53f7\u8fdb\u5165\u4fe1\u53f7\u5904\u7406\u51fd\u6570\uff08signal-catching function\uff09\uff0c\u5e76\u81ea\u52a8\u7684\u628a\u5f53\u524d\u4fe1\u53f7\u6dfb\u52a0\u5230\u8fdb\u7a0b\u7684\u4fe1\u53f7\u63a9\u7801\u91cc\u3002\u8fd9\u662f\u4e3a\u4e86\u9632\u6b62\u540e\u7eed\u4ea7\u751f\u76f8\u540c\u7684\u4fe1\u53f7\u4e2d\u65ad\u4e86\u5f53\u524d\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u7684\u6267\u884c\u3002\u5982\u679c\u6211\u4eec\u7684longjmp<\/span>\u8df3\u51fa\u4fe1\u53f7\u5904\u7406\u51fd\u6570\uff0c\u8fdb\u7a0b\u7684\u4fe1\u53f7\u63a9\u7801\u4f1a\u600e\u6837\uff1f\uff1f\uff1f<\/p>\n

\u5728FreeBSD 5.2.1\u548cMacOS X 10.3\u4e2d\uff0csetjmp<\/span>\u548clongjmp<\/span>\u4fdd\u5b58\u548c\u6062\u590d\u4fe1\u53f7\u63a9\u7801\u3002Linux 2.4.22\u548cSolaris 9\uff0c\u5e76\u4e0d\u8fd9\u4e48\u505a\u3002FreeBSD\u548cMac OS X\u63d0\u4f9b\u4e86_setjmp<\/span>\u548c_longjmp<\/span>\u51fd\u6570\uff0c\u5b83\u4eec\u5e76\u4e0d\u4fdd\u5b58\u548c\u6062\u590d\u4fe1\u53f7\u63a9\u7801\u3002<\/p>\n

POSIX.1\u5e76\u6ca1\u6709\u6307\u5b9a\u5141\u8bb8\u8fd9\u4e24\u79cd\u5f62\u5f0f\u7684\u884c\u4e3a\u5728setjmp<\/span>\u548clongjmp<\/span>\u51fd\u6570\u4e0a\uff08\u4fdd\u5b58\u548c\u6062\u590d\u4fe1\u53f7\u63a9\u7801\uff09\u3002\u800c\u662f\u7528\u4e24\u4e2a\u65b0\u51fd\u6570\u6765\u4ee3\u66ff\u2014\u2014sigsetjmp<\/span>\u548csiglongjmp<\/span>\u51fd\u6570\uff0c\u8fd9\u4e24\u4e2a\u51fd\u6570\u88ab\u5b9a\u4e49\u5728POSIX.1\u4e2d\u3002\u5f53\u4ece\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u4e2d\u8df3\u8f6c\u5206\u652f\u65f6\u5e94\u8be5\u4e00\u76f4\u4f7f\u7528\u8fd9\u4e24\u4e2a\u51fd\u6570\uff08\u56e0\u4e3a\u5b83\u4eec\u53ef\u4ee5\u4fdd\u5b58\u548c\u6062\u590d\u4fe1\u53f7\u63a9\u7801\uff09\u3002<\/p>\n\n\n\n
\n\n\n\n\n\n
\n
#include <setjmp.h>\r\n\r\nint sigsetjmp(sigjmp_buf env<\/span>, int savemask<\/span>);\r\n<\/span><\/pre>\n<\/td>\n<\/tr>\n
\n

Returns: 0 if called directly, nonzero if returning from a call to siglongjmp<\/tt><\/p>\n<\/td>\n<\/tr>\n

\n

void siglongjmp(sigjmp_buf<\/tt> env<\/tt><\/span>, int<\/tt> val<\/tt><\/span>);<\/tt><\/span><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u4e0d\u540c\u4e8esetjmp<\/span>\u548clongjmp<\/span>\u51fd\u6570\u7684\u5730\u65b9\u662fsigsetjmp<\/span>\u6709\u4e00\u4e2a\u989d\u5916\u7684\u53c2\u6570\u3002\u5982\u679csavemask<\/em>\u662f\u975e\u96f6\u503c\uff0c\u90a3\u4e48sigsetjmp<\/span>\u540c\u65f6\u5728env<\/em>\u4e2d\u4fdd\u5b58\u5f53\u524d\u8fdb\u7a0b\u7684\u4fe1\u53f7\u63a9\u7801\u3002\u5f53siglongjmp<\/span>\u88ab\u8c03\u7528\u65f6\uff0c\u5982\u679cenv\u53c2\u6570\u4e2d\u5df2\u7ecf\u4fdd\u5b58\u4e86sigsetjmp<\/span>\u4fdd\u5b58\u7684\u503c\uff0c\u90a3\u4e48siglongjmp<\/span>\u6062\u590d\u4fdd\u5b58\u7684\u4fe1\u53f7\u63a9\u7801\u3002<\/p>\n

\u4f8b\u5b50<\/h1>\n

Figure 10.20\u4e2d\u7684\u7a0b\u5e8f\u6f14\u793a\u4e86\u5f53\u4e00\u4e2a\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u81ea\u52a8\u88ab\u8c03\u7528\u65f6\u4fe1\u53f7\u63a9\u7801\u662f\u5982\u4f55\u88ab\u7cfb\u7edf\u4f7f\u7528\u7684\u3002\u8fd9\u4e2a\u7a0b\u5e8f\u540c\u6837\u6f14\u793a\u4e86sigsetjmp<\/span>\u548csiglongjmp<\/span>\u51fd\u6570\u7684\u7528\u6cd5\u3002<\/p>\n

\u8fd9\u4e2a\u7a0b\u5e8f\u6f14\u793a\u5f53siglongjmp<\/span>\u5728\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u4e2d\u7684\u4efb\u610f\u65f6\u523b\u88ab\u8c03\u7528\u7684\u6280\u672f\u3002\u6211\u4eec\u5728\u53ea\u5f53\u8c03\u7528\u4e86sigsetjmp<\/span>\u540e\u8bbe\u7f6ecanjump<\/span>\u53d8\u91cf\u503c\u4e3a\u4e00\u4e2a\u975e\u96f6\u503c\u3002\u8fd9\u4e2a\u53d8\u91cf\u5728\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u4e2d\u540c\u6837\u88ab\u68c0\u67e5\uff0c\u5e76\u4e14siglongjmp<\/span>\u51fd\u6570\u4ec5\u5728canjump<\/span>\u4e3a\u975e\u96f6\u503c\u65f6\u624d\u88ab\u8c03\u7528\u3002\u8fd9\u662f\u4e3a\u4e86\u9632\u6b62\u5f53jmpbuf\u8fd8\u6ca1\u88absigsetjmp<\/span>\u521d\u59cb\u5316\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u88ab\u8fc7\u65e9\u6216\u8fc7\u665a\u7684\u8c03\u7528\u3002\uff08\u5728\u8fd9\u4e2a\u6ca1\u6709\u5177\u4f53\u610f\u4e49\u7684\u793a\u4f8b\u4e2d\uff0c\u6211\u4eec\u5728siglongjmp<\/span>\u8c03\u7528\u540e\u5feb\u901f\u7684\u7ec8\u6b62\u8be5\u7a0b\u5e8f\uff0c\u4f46\u662f\u5728\u4e00\u4e2a\u5927\u578b\u7a0b\u5e8f\u4e2d\uff0c\u4fe1\u53f7\u5904\u7406\u7a0b\u5e8f\u5728\u8c03\u7528siglongjmp<\/span>\u540e\u8fd8\u4f1a\u4fdd\u7559\u5f88\u4e45\u3002\uff09\u8fd9\u7c7b\u68c0\u67e5\u901a\u5e38\u4e0d\u4f7f\u7528\u5728longjmp<\/span>\u51fd\u6570\u7684\u8c03\u7528\u4e2d\u3002\u56e0\u4e3a\u4e00\u4e2a\u53ef\u80fd\u5728\u4efb\u4f55\u65f6\u95f4\u53d1\u751f\uff0c\u65e0\u8bba\u5982\u4f55\u6211\u4eec\u90fd\u8981\u5728\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u4e2d\u589e\u52a0\u4e00\u4e9b\u4fdd\u62a4\u3002<\/p>\n

\u5728\u8fd9\u6211\u4eec\u4f7f\u7528\u6570\u636e\u7c7b\u578bsig_atomic_t<\/span>\uff0c\u5b83\u7531ISO C\u6807\u51c6\u5b9a\u4e49\uff0c\u7528\u6765\u5b9a\u4e49\u90a3\u4e9b\u6ca1\u88ab\u4e2d\u65ad\u624d\u80fd\u5199\u7684\u53d8\u91cf\uff08variable that can be written without being interrupted.\uff09\u3002\u8fd9\u610f\u5473\u7740\u8be5\u7c7b\u53d8\u91cf\u4e0d\u80fd\u6269\u5c55\u5230\u4f7f\u7528\u865a\u62df\u5185\u5b58\u7684\u7cfb\u7edf\u7684\u4e0d\u540c\u9875\u9762\u4e2d\uff0c\u5e76\u4e14\u53ea\u80fd\u5728\u5355\u673a\u5668\u6307\u4ee4\u7cfb\u7edf\u4e2d\u88ab\u8bbf\u95ee\u3002\u6211\u4eec\u4e00\u76f4\u4e3a\u8fd9\u7c7b\u6570\u636e\u7c7b\u578b\u4f7f\u7528ISO\u7684\u9650\u5b9a\u7b26volatile<\/span>\uff0c\u56e0\u4e3a\u8fd9\u4e2a\u53d8\u91cf\u88ab\u4e24\u4e2a\u4e0d\u540c\u7684\u7ebf\u7a0b\u63a7\u5236\u8bbf\u95ee\uff1amain<\/span>\u51fd\u6570\u548c\u5f02\u6b65\u6267\u884c\u7684\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u3002Figure 10.21\u663e\u793a\u4e86\u8be5\u7a0b\u5e8f\u7684\u65f6\u95f4\u7ebf\u3002<\/p>\n

\u6211\u4eec\u53ef\u4ee5\u628aFigure10.21\u5206\u6210\u4e09\u4e2a\u90e8\u5206\uff1a\u5de6\u8fb9\uff08\u5c5e\u4e8emain<\/span>\uff09\uff0c\u4e2d\u95f4\uff08sig_usr1<\/span>\uff09\uff0c\u548c\u53f3\u8fb9\uff08sig_alrm<\/span>\uff09\u3002\u5f53\u8fdb\u7a0b\u5728\u5de6\u8fb9\u6267\u884c\u65f6\uff0c\u5b83\u7684\u4fe1\u53f7\u63a9\u7801\u662f0\uff08\u6ca1\u6709\u4fe1\u53f7\u88ab\u963b\u585e\uff09\u3002\u5f53\u6267\u884c\u5230\u4e2d\u95f4\u65f6\uff0c\u5b83\u7684\u4fe1\u53f7\u63a9\u7801\u662fSIGUSR1<\/span>\u3002\u5f53\u6267\u884c\u5230\u53f3\u8fb9\u65f6\uff0c\u5b83\u7684\u4fe1\u53f7\u63a9\u7801\u662fSIGUSR1|SIGALRM<\/span>\u3002<\/p>\n

\u5f53FIGURE10.20\u88ab\u6267\u884c\u540e\u5b83\u7684\u8f93\u51fa\u5982\u4e0b\uff1a<\/p>\n\n\n\n
\n
   $ .\/a.out &<\/span>                      start process in background\r\n   starting main:\r\n   [1]   531                        the job-control shell prints its process ID<\/span>\r\n   $ kill -USR1 531<\/span>                 send the process<\/span> SIGUSR1\r\n   starting sig_usr1: SIGUSR1\r\n   $ in sig_alrm: SIGUSR1 SIGALRM\r\n   finishing sig_usr1: SIGUSR1\r\n   ending main:\r\n                                    just press RETURN<\/span>\r\n   [1] + Done          .\/a.out &\r\n<\/span><\/pre>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\u8f93\u51fa\u5c31\u5982\u6211\u4eec\u6240\u5e0c\u671b\u7684\u90a3\u6837\uff1a\u5f53\u6211\u4eec\u7684\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u88ab\u8c03\u7528\u65f6\uff0c\u4fe1\u53f7\u88ab\u6355\u83b7\u5e76\u6dfb\u52a0\u5230\u5f53\u524d\u8fdb\u7a0b\u7684\u4fe1\u53f7\u63a9\u7801\u4e2d<\/span>\u3002\u5f53\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u8fd4\u56de\u65f6\u539f\u59cb\u7684\u63a9\u7801\u88ab\u6062\u590d\u3002\u540c\u6837\uff0csiglongjmp<\/span>\u4e5f\u6062\u590d\u4e86\u7531sigsetjmp<\/span>\u4fdd\u5b58\u7684\u4fe1\u53f7\u63a9\u7801\u3002<\/p>\n
\u5982\u679c\u6211\u4eec\u5728linux\u5e73\u53f0\u4e0a\u6539\u53d8Figure10.20\u7684\u7a0b\u5e8f\uff0c\u628a\u8c03\u7528\u7684sigsetjmp<\/span>\u548csiglongjmp<\/span>\u51fd\u6570\u7528setjmp<\/span>\u548clongjmp<\/span>\u66ff\u6362\u3002\u6700\u540e\u4e00\u884c\u7684\u8f93\u51fa\u7ed3\u679c\u4f1a\u53d8\u6210\uff1a<\/p>\n\n\n\n
\n
 ending main: SIGUSR1<\/span><\/pre>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\u8fd9\u610f\u5473\u7740main<\/span>\u51fd\u6570\u5728\u8c03\u7528setjmp<\/span>\u540e\u7684\u6267\u884c\u8fc7\u7a0b\u4e2d\u4fe1\u53f7\u63a9\u7801\u662fSIGUSR1\u3002\u8fd9\u5e94\u8be5\u4e0d\u662f\u6211\u4eec\u6240\u5e0c\u671b\u7684\u3002<\/span><\/span><\/p>\n\n\n\n
\n
Figure 10.20. Example of signal masks, sigsetjmp<\/tt><\/span>, and siglongjmp<\/tt><\/span><\/h2>\n
#include \"apue.h\"\r\n#include <setjmp.h>\r\n#include <time.h>\r\n\r\nstatic void                         sig_usr1(int), sig_alrm(int);\r\nstatic sigjmp_buf                   jmpbuf;\r\nstatic volatile sig_atomic_t        canjump;\r\n\r\nint\r\nmain(void)\r\n{\r\n    if (signal(SIGUSR1, sig_usr1) == SIG_ERR)\r\n        err_sys(\"signal(SIGUSR1) error\");\r\n    if (signal(SIGALRM, sig_alrm) == SIG_ERR)\r\n        err_sys(\"signal(SIGALRM) error\");\r\n    pr_mask(\"starting main: \");     \/* Figure 10.14<\/a> *\/\r\n\r\n    if (sigsetjmp(jmpbuf, 1)) {\r\n        pr_mask(\"ending main: \");\r\n        exit(0);\r\n    }\r\n    canjump = 1;         \/* now sigsetjmp() is OK *\/\r\n\r\n    for ( ; ; )\r\n        pause();\r\n}\r\nstatic void\r\nsig_usr1(int signo)\r\n{\r\n    time_t  starttime;\r\n\r\n    if (canjump == 0)\r\n        return;     \/* unexpected signal, ignore *\/\r\n\r\n    pr_mask(\"starting sig_usr1: \");\r\n    alarm(3);               \/* SIGALRM in 3 seconds *\/\r\n    starttime = time(NULL);\r\n    for ( ; ; )             \/* busy wait for 5 seconds *\/\r\n        if (time(NULL) > starttime + 5)\r\n            break;\r\n    pr_mask(\"finishing sig_usr1: \");\r\n\r\n    canjump = 0;\r\n    siglongjmp(jmpbuf, 1);  \/* jump back to main, don't return *\/\r\n}\r\n\r\nstatic void\r\nsig_alrm(int signo)\r\n{\r\n    pr_mask(\"in sig_alrm: \");\r\n}\r\n<\/span><\/pre>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\"figure10-21\"<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5728APUE 7.10\u8282\uff0c\u6211\u4eec\u63cf\u8ff0\u8fc7setjmp\u548clongjmp\u51fd\u6570\uff0c\u5b83\u66fe\u88ab\u7528\u4e8e\u975e\u672c\u5730\u5206\u652f\u8df3\u8f6c\u3002longjmp\u51fd\u6570\u5e38\u88ab\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u8c03\u7528\uff0c\u7528\u4e8e\u8fd4\u56de\u7a0b\u5e8f\u7684\u4e3b\u5faa\u73af\uff0c\u800c\u4e0d…<\/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-690","post","type-post","status-publish","format-standard","hentry","category-apue"],"_links":{"self":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts\/690","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=690"}],"version-history":[{"count":7,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts\/690\/revisions"}],"predecessor-version":[{"id":699,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=\/wp\/v2\/posts\/690\/revisions\/699"}],"wp:attachment":[{"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=690"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=690"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.5x44.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=690"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}