Linux Certif

Toute la documentation sur la certification Linux LPI

poll

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#include <poll.h>



int poll(struct pollfd *fds, nfds_t nfds, int timeout);



#define _GNU_SOURCE

#include <poll.h>



int ppoll(struct pollfd *fds, nfds_t nfds, 

        const struct timespec *timeout, const sigset_t *sigmask);

ÀâÌÀ

poll() ¤Ï select(2) ¤ÈƱÍͤλŻö¤ò¹Ô¤¦¡¢¤Ä¤Þ¤ê¡¢¥Õ¥¡¥¤¥ë¥Ç¥£¥¹¥¯¥ê¥×¥¿½¸¹ç¤Î¤¤¤º¤ì¤«°ì¤Ä¤¬ I/O ¤ò¼Â¹Ô²Äǽ¤Ê¾õÂ֤ˤʤë¤Î¤òÂԤġ£

´Æ»ë¤¹¤ë¥Õ¥¡¥¤¥ë¥Ç¥£¥¹¥¯¥ê¥×¥¿½¸¹ç¤Ï¡¢ fds °ú¤­¿ô¤Ç»ØÄꤹ¤ë¡£ fds ¤Ï¡¢°Ê²¼¤Î·¿¤Î¹½Â¤ÂΤΠnfds ¸Ä¤ÎÇÛÎó¤Ç¤¢¤ë¡£

    struct pollfd {

        int   fd;         /* file descriptor */

        short events;     /* requested events */

        short revents;    /* returned events */

    };

¹½Â¤ÂΤΠfd ¤Ë¤Ï¥ª¡¼¥×¥ó¤·¤¿¥Õ¥¡¥¤¥ë¤Î¥Õ¥¡¥¤¥ë¥Ç¥£¥¹¥¯¥ê¥×¥¿¤òÆþ¤ì¤ë¡£

¹½Â¤ÂΤΠevents Í×ÁǤÏÆþÎϥѥé¥á¡¼¥¿¤Ç¡¢¥¢¥×¥ê¥±¡¼¥·¥ç¥ó¤¬¶½Ì£¤ò»ý¤Ã¤Æ¤¤¤ë¥¤¥Ù¥ó¥È¤Î ¥Ó¥Ã¥È¥Þ¥¹¥¯¤ò»ØÄꤹ¤ë¡£

revents Í×ÁǤϽÐÎϥѥé¥á¡¼¥¿¤Ç¡¢¼ÂºÝ¤Ëµ¯¤³¤Ã¤¿¥¤¥Ù¥ó¥È¤¬¥«¡¼¥Í¥ë¤Ë¤è¤êÀßÄꤵ¤ì¤ë¡£ revents ¤ÇÊÖ¤µ¤ì¤ë¥Ó¥Ã¥ÈÎó¤Ë¤Ï¡¢ events ¤Ç»ØÄꤷ¤¿¤â¤Î¤Î¤É¤ì¤«¡¢¤â¤·¤¯¤Ï POLLERR, POLLHUP, POLLNVAL ¤Î¤¦¤Á¤Î°ì¤Ä¤¬´Þ¤Þ¤ì¤ë (POLLERR, POLLHUP, POLLNVAL ¤Î 3¤Ä¤Î¥Ó¥Ã¥È¤Ï events ¤Ë»ØÄꤷ¤Æ¤â°ÕÌ£¤¬¤Ê¤¯¡¢Âбþ¤·¤¿¾õÂÖ¤¬¿¿¤Î¾ì¹ç¤Ë revents ¤ËÀßÄꤵ¤ì¤ë)¡£

¤É¤Î¥Õ¥¡¥¤¥ë¥Ç¥£¥¹¥¯¥ê¥×¥¿¤Ë¤âÍ׵ᤷ¤¿¥¤¥Ù¥ó¥È¤¬È¯À¸¤·¤Æ¤ª¤é¤º¡¢ ¥¨¥é¡¼¤âµ¯¤³¤é¤Ê¤¤¾ì¹ç¡¢ poll() ¤Ï¥¤¥Ù¥ó¥È¤Î¤¦¤Á¤¤¤º¤ì¤«°ì¤Ä¤¬È¯À¸¤¹¤ë¤Þ¤ÇÄä»ß (block) ¤¹¤ë¡£

timeout °ú¤­¿ô¤Ï poll() ¤¬Ää»ß¤¹¤ë»þ´Ö¤Î¾å¸Â¤òÀßÄꤹ¤ë¤â¤Î¤Ç¡¢¥ß¥êÉÃñ°Ì¤Ç»ØÄꤹ¤ë¡£ timeout ¤ËÉé¤ÎÃͤò»ØÄꤹ¤ë¤È¡¢¥¿¥¤¥à¥¢¥¦¥È»þ´Ö¤¬Ìµ¸Â¤È¤Ê¤ë¡£

events ¤Ë»ØÄꤷ¤¿¤ê¡¢ revents ¤ÇÊÖ¤µ¤ì¤ë¥Ó¥Ã¥È¤Ï <poll.h> ¤ÇÄêµÁ¤µ¤ì¤Æ¤¤¤ë:

POLLIN

Æɤ߽Ф·²Äǽ¤Ê¥Ç¡¼¥¿¤¬¤¢¤ë¡£

POLLPRI

Æɤ߽Ф·²Äǽ¤Ê¶ÛµÞ¥Ç¡¼¥¿ (urgent data) ¤¬¤¢¤ë (Î㤨¤Ð¡¢TCP ¥½¥±¥Ã¥È¤ÎÂÓ°è³° (out-of-band data) ¥Ç¡¼¥¿¤ò¼õ¿®¤·¤¿¾ì¹ç¤ä¡¢ ¥Ñ¥±¥Ã¥È¥â¡¼¥É¤Îµ¼»÷üËö¤Î¥Þ¥¹¥¿¤¬¥¹¥ì¡¼¥Ö¦¤ÎÊѲ½¤ò¸«¤Ä¤±¤¿¤È¤­)¡£

POLLOUT

½ñ¤­¹þ¤ß¤¬Ää»ß (block) ¤·¤Ê¤¤¾õÂ֤Ǥ¢¤ë¡£

POLLRDHUP (Linux 2.6.17 °Ê¹ß)

¥¹¥È¥ê¡¼¥à¥½¥±¥Ã¥È¤Î¾ü¤¬¡¢¥³¥Í¥¯¥·¥ç¥ó¤ò close ¤·¤¿¤«¡¢ ¥³¥Í¥¯¥·¥ç¥ó¤Î½ñ¤­¹þ¤ß¦¤ò shutdown ¤·¤¿¡£ ¤³¤ÎÄêµÁ¤òÍ­¸ú¤Ë¤¹¤ë¤Ë¤Ï¡¢ _GNU_SOURCE µ¡Ç½¸¡ºº¥Þ¥¯¥í¤òÄêµÁ¤·¤Ê¤±¤ì¤Ð¤Ê¤é¤Ê¤¤¡£

POLLERR

¥¨¥é¡¼¾õÂÖ (½ÐÎϤξì¹ç¤Î¤ß)¡£

POLLHUP

¥Ï¥ó¥°¥¢¥Ã¥×¤·¤¿ (½ÐÎϤξì¹ç¤Î¤ß)¡£

POLLNVAL

ÉÔÀµ¤ÊÍ×µá: fd ¤¬¥ª¡¼¥×¥ó¤µ¤ì¤Æ¤¤¤Ê¤¤ (½ÐÎϤξì¹ç¤Î¤ß)¡£

_XOPEN_SOURCE ¤òÄêµÁ¤·¤Æ¥³¥ó¥Ñ¥¤¥ë¤·¤¿¾ì¹ç¤Ë¤Ï¡¢°Ê²¼¤ÎÄêµÁ¤â¹Ô¤ï¤ì¤ë¡£ ¤¿¤À¤·¡¢¾åµ­¤Î¥ê¥¹¥È¤Ë¤¢¤ë¥Ó¥Ã¥È°Ê¾å¤Î¾ðÊó¤¬ÆÀ¤é¤ì¤ëÌõ¤Ç¤Ï¤Ê¤¤¡£

POLLRDNORM

POLLIN ¤ÈƱ¤¸¡£

POLLRDBAND

Í¥ÀèÂÓ°è¥Ç¡¼¥¿ (priority band data) ¤¬Æɤ߽Ф·²Äǽ¤Ç¤¢¤ë (ÉáÄÌ¤Ï Linux ¤Ç¤Ï»ÈÍѤµ¤ì¤Ê¤¤)¡£

POLLWRNORM

POLLOUT ¤ÈƱ¤¸¡£

POLLWRBAND

Í¥ÀèÂÓ°è¥Ç¡¼¥¿ (priority data) ¤¬½ñ¤­¹þ¤ß²Äǽ¤Ç¤¢¤ë¡£

Linux ¤Ç¤Ï POLLMSG ¤âÄêµÁ¤µ¤ì¤Æ¤¤¤ë¤¬¡¢»ÈÍѤµ¤ì¤Æ¤¤¤Ê¤¤¡£

ppoll()

poll() ¤È ppoll() ¤Î´Ø·¸¤Ï select(2) ¤È pselect(2) ¤Î´Ø·¸¤ÈƱ¤¸¤è¤¦¤Ê¤â¤Î¤Ç¤¢¤ë: pselect(2) ¤ÈƱÍͤˡ¢ ppoll() ¤ò»È¤¦¤È¡¢¥¢¥×¥ê¥±¡¼¥·¥ç¥ó¤Ï¥Õ¥¡¥¤¥ë¥Ç¥£¥¹¥¯¥ê¥×¥¿¤Î¾õÂÖÊѲ½ ¤â¤·¤¯¤Ï¥·¥°¥Ê¥ë¤ÎÊ᪤ò°ÂÁ´¤ËÂԤĤ³¤È¤¬¤Ç¤­¤ë¡£

timeout °ú¤­¿ô¤Î°ã¤¤¤ò½ü¤¯¤È¡¢°Ê²¼¤Î ppoll() ¤Î¸Æ¤Ó½Ð¤·¤Ï¡¢

    ready = ppoll(&fds, nfds, timeout, &sigmask);

¼¡¤Î¥³¡¼¥ë¤ò atomic ¤Ë¼Â¹Ô¤¹¤ë¤Î¤ÈÅù²Á¤Ç¤¢¤ë¡£

    sigset_t origmask;



    sigprocmask(SIG_SETMASK, &sigmask, &origmask);

    ready = poll(&fds, nfds, timeout);

    sigprocmask(SIG_SETMASK, &origmask, NULL);

¤Ê¤¼ ppoll() ¤¬É¬ÍפʤΤ«¤Ë¤Ä¤¤¤Æ¤ÎÀâÌÀ¤Ï pselect(2) ¤ÎÀâÌÀ¤ò»²¾È¤Î¤³¤È¡£

timeout °ú¤­¿ô¤Ï ppoll() ¤¬Ää»ß¤¹¤ë»þ´Ö¤Î¾å¸Â¤ò»ØÄꤹ¤ë¤â¤Î¤Ç¤¢¤ë¡£ ¤³¤Î°ú¤­¿ô¤Ë¤Ï°Ê²¼¤Î·¿¤Î¹½Â¤ÂΤؤΥݥ¤¥ó¥¿¤ò»ØÄꤹ¤ë¡£

struct timespec {

    long    tv_sec;         /* seconds */

    long    tv_nsec;        /* nanoseconds */

};

timeout ¤Ë NULL ¤¬»ØÄꤵ¤ì¤¿¾ì¹ç¡¢ ppoll ¤Ï̵¸Â¤ËÄä»ß¤¹¤ë¤³¤È¤¬¤¢¤êÆÀ¤ë¡£

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EBADF

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EFAULT

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EINTR

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EINVAL

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ENOMEM

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¥Ð¡¼¥¸¥ç¥ó

poll() ¥·¥¹¥Æ¥à¥³¡¼¥ë¤Ï Linux 2.1.23 ¤ÇƳÆþ¤µ¤ì¤¿¡£ poll() ¥é¥¤¥Ö¥é¥ê¡¦¥³¡¼¥ë¤Ï libc 5.4.28 ¤«¤éƳÆþ¤µ¤ì¤¿ (¤³¤ì¤Ï¥«¡¼¥Í¥ë¤¬ poll() ¥·¥¹¥Æ¥à¥³¡¼¥ë¤ò¥µ¥Ý¡¼¥È¤·¤Æ¤¤¤Ê¤¤¾ì¹ç¤Ë select(2) ¤ò»ÈÍѤ·¤Æ¥¨¥ß¥å¥ì¡¼¥È¤ò¹Ô¤¦)¡£

ppoll() ¥·¥¹¥Æ¥à¥³¡¼¥ë¤Ï ¥«¡¼¥Í¥ë 2.6.16 ¤Ç Linux ¤ËÄɲ䵤줿¡£ ppoll() ¥é¥¤¥Ö¥é¥ê¥³¡¼¥ë¤Ï glibc 2.4 ¤ËÄɲ䵤줿¡£

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Linux ¤Ç¤ÎÃí°Õ

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