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write, writev, pwrite — ???Ϥν?????

?饤?֥???

Standard C Library (libc, -lc)

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<sys/types.h> <sys/uio.h> <unistd.h> ssize_t write(int d, const void *buf, size_t nbytes) ssize_t writev(int d, const struct iovec *iov, int iovcnt) ssize_t pwrite(int d, const void *buf, size_t nbytes, off_t offset)

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write() ?????ƥॳ?????ϡ? buf ???ؤ??Хåե????鵭?һ? d ?????Ȥ??륪?֥??????Ȥ? nbytes ?Υǡ??????񤭹??⤦?Ȥ??ޤ??? writev() ?????ƥॳ??????Ʊ?ͤ?ư???򤷤ޤ?????iov[0], iov[1], ..., iov[iovcnt-1] ?Ȥ??? iov ?????Υ????Ф????ꤹ?? iovcnt ?Хåե????????ϥǡ????򽸤??ޤ??? pwrite() ?????ƥॳ??????Ʊ????ǽ???¹Ԥ??ޤ??????ե??????ݥ??󥿤??????????ˡ? ?ե????????????????˽񤭹??ߤޤ???

writev() ?Ǥϡ? iovec ??¤?Τ??ʲ??Τ褦???????????Ƥ??ޤ?:

struct iovec {
	void   *iov_base;    /* ?١??????ɥ쥹 */
	size_t  iov_len;     /* Ĺ?? */
};

?? iovec ?????ȥ??ϡ??񤭹????ǡ????????????????Υ١??????ɥ쥹?? ?ΰ???Ĺ???????ꤷ?ޤ??? writev() ?????ƥॳ?????ϡ??????ΰ????Τ??񤭹????Ǥ??鼡?˿ʤߤޤ???

????????ǽ?????륪?֥??????ȤǤϡ? write() ?? d ?˴?Ϣ?????ݥ??󥿤????ꤹ?????֤dz??Ϥ??ޤ??? lseek(2) ?򻲾Ȥ??Ƥ????????? write() ?????????ȡ??ݥ??󥿤Ͻ񤭹??ޤ줿?Х??ȿ??????ʤߤޤ???

????????ǽ???ʤ????֥??????ȤǤϡ????˸??߰??֤????񤭹??ߤޤ??? ???Τ褦?ʥ??֥??????Ȥ˴?Ϣ?????ݥ??󥿤??ͤ?̤?????Ǥ???

?¥桼?????????ѥ桼???Ǥʤ????硢 write() ?ϡ??桼?? ID ?????ӥåȤ??ե??????ǥ??ꥢ???ޤ??? ?????ˤ??ꡢ?????ѥ桼??????ͭ?????????߲?ǽ?ʥ桼?? ID ?????ե??????? “?ᤨ??” ?桼???ϡ??????ƥॻ???????ƥ??????ˤǤ??ʤ??ʤ??ޤ???

?????åȤΤ褦?ˡ??ե????????αƶ????????륪?֥??????Ȥ? ???֥??å????? I/O ?????Ѥ????ȡ? write() ?? writev() ?ϡ??׵ᤷ?????꾯?ʤ??Х??ȿ????񤭹??ळ?Ȥ??????ޤ??? ?????ͤ????դ?????ǽ?ʾ????ˤϥ??ڥ졼???????λĤ??????ٻ?Ƥ?????????

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???????????˴?λ?????ȡ??񤭹??ޤ줿?Х??ȿ????֤????ޤ??? ?????Ǥʤ??????? -1 ???֤??졢???顼?򼨤??????˥??????Х??ѿ? errno ?????ꤵ???ޤ???

???顼

write(), writev() ?????? pwrite() ?????ƥॳ?????ϡ??ʲ??ξ????˥??顼?Ȥʤꡢ ?ե??????ݥ??󥿤??ѹ????줺?˻Ĥ??ޤ?:

[EBADF]

d ???????????????Ѥ˳????줿ͭ???ʵ??һҤǤϤ????ޤ?????

[EPIPE]

?ץ??????ˤ????ɼ????Ѥ˳??????Ƥ??ʤ??ѥ??פ˽񤭹??⤦?Ȥ??ޤ?????

[EPIPE]

?̿??????Υ????åȤ???³???Ƥ??ʤ??????? SOCK_STREAM ?Υ????åȤ˽񤭹??⤦?Ȥ??ޤ?????

[EFBIG]

?ץ??????Υե????륵???????¤??????ե????륵???????ۤ????ե??????? ?񤭹??⤦?Ȥ??ޤ?????

[EFAULT]

iov ?ΰ??????ޤ??ϥե??????˽񤭹????ǡ????ϡ? ?ץ??????˳??????Ƥ??줿???ɥ쥹???֤??ϰϳ????ؤ??Ƥ??ޤ???

[EINVAL]

d ?˴?Ϣ?????ݥ??󥿤????ˤʤäƤ??ޤ???

[ENOSPC]

?ե????????ޤ??ե????륷???ƥ??ˡ???ʬ?ʥ??ڡ??????ĤäƤ??ޤ?????

[EDQUOT]

?ե????????ޤ??ե????륷???ƥ??Υ桼???Υǥ??????֥??å??????̤? ?Ȥ??Ԥ??????Ƥ??ޤ???

[EIO]

?ե????륷???ƥ????ɤ߽񤭤??Ƥ????֤??????ϥ??顼??ȯ?????ޤ?????

[EINTR]

?????ߤ???λ???????˥????ʥ뤬???????ߤޤ?????

[EAGAIN]

?ե??????????֥??å??????????Ϥΰ????Ĥ??????֤ǡ??????⡢ ?????˥ǡ??????񤭹????????֤ǤϤ????ޤ?????

[EROFS]

???饤??????Ƭ?ˤ????ǥ????????٥??ΰ??˽????ߤ??Ԥ????Ȥ??ޤ????? ?ǥ????????٥??ΰ??ؤν????ߤ?ͭ???ˤ????ˤ? disklabel(8) -W ?򻲾Ȥ??Ƥ?????????

writev() ?ϡ??ʲ??Υ??顼???᤹???Ȥ??????ޤ?:

[EDESTADDRREQ]

connect(2) ?????Ѥ??ƽ??????襢?ɥ쥹?????ꤷ?? UNIX ?ɥᥤ???ǡ????????ॽ???åȤ˽񤭹????????ˡ????????褬???ѤǤ??ޤ?????

[EINVAL]

iovcnt ?????? 0 ?ʲ??ˤʤäƤ??뤫?? IOV_MAX ???ꡢ?礭???ʤäƤ??ޤ???

[EINVAL]

iov ???? iov_len ?ͤ? 1 ?Ĥ????ˤʤäƤ??ޤ???

[EINVAL]

iov ???? iov_len ?ͤι??פ???32 ?ӥå??????򥪡??Хե??????ޤ?????

[ENOBUFS]

?????åȤ˽񤭽Ф??Ƥ??????? mbuf ?Υס??????Ȥ??Ԥ????ޤ?????

pwrite() ?????ƥॳ?????ϡ??ʲ??Υ??顼???᤹???Ȥ??????ޤ?:

[EINVAL]

offset ???ͤ????Ǥ???

[ESPIPE]

?ե????뵭?һҤ????ѥ??ס??????åȡ?FIFO ?˴?Ϣ???Ƥ??ޤ???

??Ϣ????

fcntl(2), lseek(2), open(2), pipe(2), select(2)

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write() ?????ƥॳ?????ϡ? IEEE Std 1003.1-1990 (“POSIX.1”) ??Ŭ?礷?Ƥ??ޤ??? writev() ?????ƥॳ?????? pwrite() ?????ƥॳ?????ϡ? X/Open Portability Guide Issue 4, Version 2 (“XPG4.2”) ??Ŭ?礷?Ƥ??ޤ???

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pwrite() ?ؿ??ϡ? AT&T System V Release 4 UNIX ???о줷?ޤ????? writev() ?????ƥॳ?????ϡ? 4.2BSD ???о줷?ޤ????? write() ?ؿ??ϡ? Version 6 AT&T UNIX ???о줷?ޤ?????