{"id":3545,"date":"2017-08-18T20:57:57","date_gmt":"2017-08-18T12:57:57","guid":{"rendered":"https:\/\/ixyzero.com\/blog\/?p=3545"},"modified":"2017-08-18T20:57:57","modified_gmt":"2017-08-18T12:57:57","slug":"linux%e4%b8%8bc%e8%af%ad%e8%a8%80%e4%b8%adfcntl%e5%87%bd%e6%95%b0%e7%94%a8%e6%b3%95%e8%af%b4%e6%98%8e","status":"publish","type":"post","link":"https:\/\/ixyzero.com\/blog\/archives\/3545.html","title":{"rendered":"Linux\u4e0bC\u8bed\u8a00\u4e2dfcntl\u51fd\u6570\u7528\u6cd5\u8bf4\u660e"},"content":{"rendered":"

=Start=<\/p>\n

\u7f18\u7531\uff1a<\/h4>\n

\u5b66\u4e60\u3001\u63d0\u9ad8\u9700\u8981<\/p>\n

\u6b63\u6587\uff1a<\/h4>\n

\u53c2\u8003\u89e3\u7b54\uff1a<\/h5>\n

fcntl – manipulate file descriptor (\u64cd\u4f5c\u6587\u4ef6\u63cf\u8ff0\u7b26)<\/p>\n

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#include <unistd.h><\/code><\/div>\n
#include <fcntl.h><\/code><\/div>\n
<\/div>\n
int<\/code>\u00a0fcntl(<\/code>int<\/code>\u00a0fd,\u00a0<\/code>int<\/code>\u00a0cmd, ...\u00a0<\/code>\/* arg *\/<\/code>\u00a0);<\/code><\/div>\n
\u00a0<\/code><\/div>\n
\/\/ fcntl()\u51fd\u6570\u5bf9\u7531\u53c2\u6570 fd \u6307\u5b9a\u7684\u6587\u4ef6\u8fdb\u884c\u7531\u53c2\u6570 cmd \u6307\u5b9a\u7684\u64cd\u4f5c\uff1b\u7b2c\u4e09\u4e2a\u53c2\u6570 arg \u662f\u53ef\u9009\u7684\uff0c\u4e14\u7531\u7b2c\u4e8c\u4e2a\u53c2\u6570 cmd \u51b3\u5b9a<\/code><\/div>\n
int<\/code>\u00a0fcntl(<\/code>int<\/code>\u00a0fd,\u00a0<\/code>int<\/code>\u00a0cmd);<\/code><\/div>\n
int<\/code>\u00a0fcntl(<\/code>int<\/code>\u00a0fd,\u00a0<\/code>int<\/code>\u00a0cmd,\u00a0<\/code>int<\/code>\u00a0arg);<\/code><\/div>\n
int<\/code>\u00a0fcntl(<\/code>int<\/code>\u00a0fd,\u00a0<\/code>int<\/code>\u00a0cmd, struct flock *lock);<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

fcntl()\u51fd\u6570\u4e3b\u8981\u67095\u79cd\u529f\u80fd\uff1a<\/p>\n

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  • \u590d\u5236\u4e00\u4e2a\u73b0\u6709\u7684\u63cf\u8ff0\u7b26(cmd=F_DUPFD\/F_DUPFD_CLOEXEC)<\/li>\n
  • \u83b7\u5f97\uff0f\u8bbe\u7f6e\u6587\u4ef6\u63cf\u8ff0\u7b26\u6807\u8bb0(cmd=F_GETFD\/F_SETFD)<\/li>\n
  • \u83b7\u5f97\uff0f\u8bbe\u7f6e\u6587\u4ef6\u72b6\u6001\u6807\u8bb0<\/span><\/strong>(cmd=F_GETFL\/F_SETFL) #\u5e38\u7528<\/li>\n
  • \u83b7\u5f97\uff0f\u8bbe\u7f6e\u5f02\u6b65I\/O\u6240\u6709\u6743(cmd=F_GETOWN\/F_SETOWN)<\/li>\n
  • \u83b7\u5f97\uff0f\u8bbe\u7f6e\u8bb0\u5f55\u9501<\/span>(cmd=F_GETLK\/F_SETLK\/F_SETLKW) #\u5e38\u7528<\/li>\n<\/ul>\n
    \n

    \u83b7\u53d6\u3001\u8bbe\u7f6e\u6587\u4ef6\u72b6\u6001\u6807\u8bb0\u6837\u4f8b\uff1a<\/p>\n

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    #include <unistd.h><\/code><\/div>\n
    #include <fcntl.h><\/code><\/div>\n
    #include <stdio.h><\/code><\/div>\n
    #include <stdlib.h><\/code><\/div>\n
    #include <errno.h><\/code><\/div>\n
    #include <string.h><\/code><\/div>\n
    <\/div>\n
    #define ERR_EXIT(m) \\<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>do<\/code>\u00a0{ \\<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>perror(m); \\<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>exit(EXIT_FAILURE); \\<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>}\u00a0<\/code>while<\/code>(<\/code>0<\/code>)<\/code><\/div>\n
    <\/div>\n
    void<\/code>\u00a0set_flag(<\/code>int<\/code>,\u00a0<\/code>int<\/code>);<\/code><\/div>\n
    void<\/code>\u00a0clr_flag(<\/code>int<\/code>,\u00a0<\/code>int<\/code>);<\/code><\/div>\n
    <\/div>\n
    int<\/code>\u00a0main(<\/code>int<\/code>\u00a0argc,\u00a0<\/code>char<\/code>\u00a0*argv[])<\/code><\/div>\n
    {<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>char<\/code>\u00a0buf[<\/code>1024<\/code>] = {<\/code>0<\/code>};<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>int<\/code>\u00a0ret;<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>\/\/ int flags;<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>\/\/ flags = fcntl(0, F_GETFL, 0);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>\/\/ if (flags == -1)<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>\/\/\u00a0\u00a0\u00a0\u00a0 ERR_EXIT(\"fcntl get flag error\");<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>\/\/ printf(\"flags = %d\\n\", flags);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>\/\/ ret = fcntl(0, F_GETFL, flags | O_NONBLOCK); \/\/\u8bbe\u7f6e\u4e3a\u975e\u963b\u585e,\u4f46\u4e0d\u66f4\u6539\u5176\u4ed6\u72b6\u6001<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>\/\/ if (ret == -1)<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>\/\/\u00a0\u00a0\u00a0\u00a0 ERR_EXIT(\"fcntl set flag error\");<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>\/\/ printf(\"flags = %d\\n\", flags);<\/code><\/div>\n
    <\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>errno =\u00a0<\/code>0<\/code>;<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>set_flag(<\/code>0<\/code>, O_NONBLOCK);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>ret = read(<\/code>0<\/code>, buf,\u00a0<\/code>1024<\/code>);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0(ret == -<\/code>1<\/code>) {<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"errno = %d (%s)\\n\"<\/code>, errno, strerror(errno));<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>ERR_EXIT(<\/code>\"read error\"<\/code>);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
    <\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"buf=%s\\n\"<\/code>, buf);<\/code><\/div>\n
    <\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>return<\/code>\u00a00<\/code>;<\/code><\/div>\n
    }<\/code><\/div>\n
    <\/div>\n
    void<\/code>\u00a0set_flag(<\/code>int<\/code>\u00a0fd,\u00a0<\/code>int<\/code>\u00a0flags)<\/code><\/div>\n
    {<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>int<\/code>\u00a0val;<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>val = fcntl(fd, F_GETFL,\u00a0<\/code>0<\/code>);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0(val == -<\/code>1<\/code>) {<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>ERR_EXIT(<\/code>\"fcntl get flag error\"<\/code>);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>val |= flags;<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0(fcntl(fd, F_SETFL, val) <\u00a0<\/code>0<\/code>) {<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>ERR_EXIT(<\/code>\"fcntl set flag error\"<\/code>);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
    }<\/code><\/div>\n
    <\/div>\n
    void<\/code>\u00a0clr_flag(<\/code>int<\/code>\u00a0fd,\u00a0<\/code>int<\/code>\u00a0flags)<\/code><\/div>\n
    {<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>int<\/code>\u00a0val;<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>val = fcntl(fd, F_GETFL,\u00a0<\/code>0<\/code>);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0(val == -<\/code>1<\/code>)<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>ERR_EXIT(<\/code>\"fcntl get flag error\"<\/code>);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>val &= ~flags;<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0(fcntl(fd, F_SETFL, val) <\u00a0<\/code>0<\/code>)<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>ERR_EXIT(<\/code>\"fcntl set flag error\"<\/code>);<\/code><\/div>\n
    }<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

    &<\/p>\n

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    \u56e0\u4e3a\u5c06\u6807\u51c6\u8f93\u5165\u7684\u72b6\u6001\u66f4\u6539\u4e3a\u975e\u963b\u585e\uff0c\u5219read\u4e0d\u4f1a\u963b\u585e\u7b49\u5f85\u8f93\u5165\u800c\u7acb\u5373\u8fd4\u56de\u9519\u8bef\uff0cerrno\u5c06\u88ab\u7f6e\u4e3aEAGAIN\uff0c\u5373\u53ef\u4ee5\u91cd\u65b0\u5c1d\u8bd5\u3002\u4e0b\u9762\u662f\u5b9e\u9645\u6d4b\u8bd5\u7684\u60c5\u51b5\uff1a<\/code><\/div>\n
    $ .\/a.out<\/code><\/div>\n
    errno =\u00a0<\/code>35<\/code>\u00a0(Resource temporarily unavailable)<\/code><\/div>\n
    read error: Resource temporarily unavailable<\/code><\/div>\n
    $<\/code><\/div>\n
    $ echo\u00a0<\/code>\"hi\"<\/code>\u00a0| .\/a.out<\/code><\/div>\n
    buf=hi<\/code><\/div>\n
    <\/div>\n
    $<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

    &<\/p>\n

    \u5e38\u89c1\u7528\u6cd5\u5c31\u662f\u2014\u2014\u5c06socket fd\u8bbe\u7f6e\u4e3a\u975e\u963b\u585e\u6a21\u5f0f\uff1a<\/p>\n

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    static<\/code>\u00a0int<\/code>\u00a0make_socket_non_blocking (<\/code>int<\/code>\u00a0sfd)<\/code><\/div>\n
    {<\/code><\/div>\n
    \u00a0\u00a0<\/code>int<\/code>\u00a0flags, s;<\/code><\/div>\n
    \u00a0\u00a0<\/code>flags = fcntl (sfd, F_GETFL,\u00a0<\/code>0<\/code>);<\/code><\/div>\n
    \u00a0\u00a0<\/code>if<\/code>\u00a0(flags == -<\/code>1<\/code>) {<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>perror (<\/code>\"fcntl\"<\/code>);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>return<\/code>\u00a0-<\/code>1<\/code>;<\/code><\/div>\n
    \u00a0\u00a0<\/code>}<\/code><\/div>\n
    \u00a0\u00a0<\/code>flags |= O_NONBLOCK;<\/code><\/div>\n
    \u00a0\u00a0<\/code>s = fcntl (sfd, F_SETFL, flags);<\/code><\/div>\n
    \u00a0\u00a0<\/code>if<\/code>\u00a0(s == -<\/code>1<\/code>) {<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>perror (<\/code>\"fcntl\"<\/code>);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>return<\/code>\u00a0-<\/code>1<\/code>;<\/code><\/div>\n
    \u00a0\u00a0<\/code>}<\/code><\/div>\n
    \u00a0\u00a0<\/code>return<\/code>\u00a00<\/code>;<\/code><\/div>\n
    }<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

    \u83b7\u53d6\u3001\u8bbe\u7f6e\u6587\u4ef6\u9501\u6837\u4f8b\uff1a<\/p>\n

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    #include <unistd.h><\/code><\/div>\n
    #include <fcntl.h><\/code><\/div>\n
    #include <stdio.h><\/code><\/div>\n
    #include <stdlib.h><\/code><\/div>\n
    #include <errno.h><\/code><\/div>\n
    #include <string.h><\/code><\/div>\n
    <\/div>\n
    #define ERR_EXIT(m) \\<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>do<\/code>\u00a0{ \\<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>perror(m); \\<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>exit(EXIT_FAILURE); \\<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>}\u00a0<\/code>while<\/code>(<\/code>0<\/code>)<\/code><\/div>\n
    <\/div>\n
    int<\/code>\u00a0main(<\/code>int<\/code>\u00a0argc,\u00a0<\/code>char<\/code>\u00a0*argv[])<\/code><\/div>\n
    {<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>int<\/code>\u00a0fd;<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>fd = open(<\/code>\"test2.txt\"<\/code>, O_CREAT | O_RDWR | O_TRUNC,\u00a0<\/code>0664<\/code>);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0(fd == -<\/code>1<\/code>)<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>ERR_EXIT(<\/code>\"open error\"<\/code>);<\/code><\/div>\n
    <\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>\/* \u53ea\u6709\u5bf9\u6587\u4ef6\u6709\u76f8\u5e94\u7684\u8bfb\u5199\u6743\u9650\u624d\u80fd\u65bd\u52a0\u5bf9\u5e94\u7684\u6587\u4ef6\u9501 *\/<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>struct flock lock;<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>memset(&lock,\u00a0<\/code>0<\/code>, sizeof(lock));<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>lock.l_type = F_WRLCK;\u00a0<\/code>\/\/ \u6392\u4ed6\u9501,\u5373\u4e0d\u5141\u8bb8\u5176\u4ed6\u8fdb\u7a0b\u518d\u5bf9\u5176\u52a0\u4efb\u4f55\u7c7b\u578b\u7684\u9501\uff0c\u4f46\u8bfb\u9501\uff08\u5171\u4eab\u9501\uff09\u5141\u8bb8<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>lock.l_whence = SEEK_SET;<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>lock.l_start =\u00a0<\/code>0<\/code>;\u00a0<\/code>\/\/\u4ece\u6587\u4ef6\u5f00\u5934\u5f00\u59cb\u9501\u5b9a<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>lock.l_len =\u00a0<\/code>0<\/code>;\u00a0<\/code>\/\/ \u6587\u4ef6\u5168\u90e8\u5185\u5bb9\u9501\u4f4f<\/code><\/div>\n
    <\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0(fcntl(fd, F_SETLK, &lock) ==\u00a0<\/code>0<\/code>)<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>{<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>\/* \u82e5\u4e3aF_SETLKW,\u8fd9\u65f6\u5982\u679c\u9501\u5df2\u7ecf\u88ab\u5176\u4ed6\u8fdb\u7a0b\u5360\u7528\uff0c\u5219\u6b64\u8fdb\u7a0b\u4f1a\u963b\u585e\u76f4\u5230\u5176\u4ed6\u8fdb\u7a0b\u91ca\u653e\u9501*\/<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"lock success\\n\"<\/code>);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"press any key to unlock\\n\"<\/code>);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>getchar();<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>lock.l_type = F_UNLCK;<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0(fcntl(fd, F_SETLK, &lock) ==\u00a0<\/code>0<\/code>)<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"unlock success\\n\"<\/code>);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>else<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>ERR_EXIT(<\/code>\"unlock fail\"<\/code>);<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>}<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>else<\/code><\/div>\n
    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>ERR_EXIT(<\/code>\"lock fail\"<\/code>);<\/code><\/div>\n
    <\/div>\n
    \u00a0\u00a0\u00a0\u00a0<\/code>return<\/code>\u00a00<\/code>;\u00a0<\/code>\/\/\u8fdb\u7a0b\u9000\u51fa\u4f1a\u5bf9\u6240\u6709\u6587\u4ef6\u89e3\u9501<\/code><\/div>\n
    }<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

    \u5148\u5728\u4e00\u4e2a\u7ec8\u7aef\u6267\u884c\u7a0b\u5e8f\uff1a
    \n$ .\/a.out
    \nlock success
    \npress any key to unlock<\/p>\n

    \u73b0\u5728\u6587\u4ef6\u5df2\u7ecf\u88ab\u9501\u4f4f\u4e86\uff0c\u800c\u4e14\u6ca1\u6709\u6309\u4e0b\u4efb\u4f55\u6309\u952e\uff0c\u6240\u4ee5\u5361\u5728\u8fd9\u91cc\uff0c\u4e5f\u8fd8\u6ca1\u89e3\u9501\uff0c\u63a5\u7740\u5728\u53e6\u4e00\u4e2a\u7ec8\u7aef\u518d\u6b21\u6267\u884c\u540c\u4e00\u4e2a\u7a0b\u5e8f\uff1a
    \n$ .\/a.out
    \nlock fail: Resource temporarily unavailable<\/p>\n

    \u4f1a\u7acb\u5373\u8fd4\u56de\u9519\u8bef\uff0c\u56e0\u4e3a\u6211\u4eec\u5e0c\u671b\u65bd\u52a0\u7684\u662f\u6392\u4ed6\u9501\uff0c\u800c\u73b0\u5728\u524d\u9762\u4e00\u4e2a\u8fdb\u7a0b\u6b63\u5728\u5360\u7528\u5199\u9501\u8fd8\u6ca1\u91ca\u653e\uff0c\u6240\u4ee5\u5c1d\u8bd5\u65bd\u52a0\u9501\u5931\u8d25\uff0c\u800c\u5982\u679cfcntl()\u51fd\u6570\u7684cmd\u8bbe\u7f6e\u4e3a F_SETLKW\uff0c\u5373\u5e26w\u7684\u7248\u672c\uff0c\u5219\u6b64\u8fdb\u7a0b\u4f1a\u4e00\u76f4\u963b\u585e\u76f4\u5230\u524d\u9762\u4e00\u4e2a\u8fdb\u7a0b\u91ca\u653e\u4e86\u9501\u3002<\/p>\n

    \u53c2\u8003\u94fe\u63a5\uff1a<\/h5>\n

    linux\u7cfb\u7edf\u7f16\u7a0b\u4e4b\u6587\u4ef6\u4e0eI\/O\uff08\u516d\uff09\uff1afcntl \u51fd\u6570\u4e0e\u6587\u4ef6\u9501<\/strong><\/span> #nice
    \nhttp:\/\/blog.csdn.net\/jnu_simba\/article\/details\/8927115<\/a>
    \n    http:\/\/cissco.iteye.com\/blog\/266924<\/a><\/p>\n

    http:\/\/man7.org\/linux\/man-pages\/man2\/fcntl.2.html<\/a><\/p>\n

    C\u8bed\u8a00fcntl()\u51fd\u6570\uff1a\u6587\u4ef6\u63cf\u8ff0\u8bcd\u64cd\u4f5c\u51fd\u6570
    \n    http:\/\/c.biancheng.net\/cpp\/html\/233.html<\/a><\/p>\n

    Linux C fcntl()\u51fd\u6570\u8be6\u89e3
    \n    http:\/\/www.cnblogs.com\/phpgo\/p\/5693859.html<\/a>
    \n    https:\/\/stackoverflow.com\/questions\/6125068\/what-does-the-fd-cloexec-fcntl-flag-do<\/a><\/p>\n

    =END=<\/p>\n","protected":false},"excerpt":{"rendered":"

    =Start= \u7f18\u7531\uff1a \u5b66\u4e60\u3001\u63d0\u9ad8\u9700\u8981 \u6b63\u6587\uff1a \u53c2\u8003\u89e3\u7b54\uff1a fcntl – manipulate […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23,11,7],"tags":[100,917,30,918],"class_list":["post-3545","post","type-post","status-publish","format-standard","hentry","category-knowledgebase-2","category-linux","category-programing","tag-c","tag-fcntl","tag-linux","tag-o_nonblock"],"views":6968,"_links":{"self":[{"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/posts\/3545","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/comments?post=3545"}],"version-history":[{"count":1,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/posts\/3545\/revisions"}],"predecessor-version":[{"id":3546,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/posts\/3545\/revisions\/3546"}],"wp:attachment":[{"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/media?parent=3545"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/categories?post=3545"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/tags?post=3545"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}