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[linuxjm/jm.git] / manual / LDP_man-pages / draft / man3 / qsort.3

.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" References consulted:
.\"     Linux libc source code
.\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
.\"     386BSD man pages
.\"
.\" Modified 1993-03-29, David Metcalfe
.\" Modified 1993-07-24, Rik Faith (faith@cs.unc.edu)
.\" 2006-01-15, mtk, Added example program.
.\"
.\" FIXME glibc 2.8 added qsort_r(), which needs to be documented.
.\"
.\" Japanese Version Copyright (c) 1997 YOSHINO Takashi
.\"       all rights reserved.
.\" Translated 1997-01-21, YOSHINO Takashi <yoshino@civil.jcn.nihon-u.ac.jp>
.\" Updated & Modified 2004-06-06, Yuichi SATO <ysato444@yahoo.co.jp>
.\" Updated 2006-01-18, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\"
.TH QSORT 3 2009-09-15 "" "Linux Programmer's Manual"
.\"O .SH NAME
.SH ̾Á°
.\"O qsort \- sorts an array
qsort \- ÇÛÎó¤òʤÙÊѤ¨¤ë
.\"O .SH SYNOPSIS
.SH ½ñ¼°
.nf
.B #include <stdlib.h>
.sp
.BI "void qsort(void *" base ", size_t " nmemb ", size_t " size ,
.BI "           int(*" compar ")(const void *, const void *));"
.fi
.\"O .SH DESCRIPTION
.SH ÀâÌÀ
.\"O The
.\"O .BR qsort ()
.\"O function sorts an array with \fInmemb\fP elements of
.\"O size \fIsize\fP.
.\"O The \fIbase\fP argument points to the start of the
.\"O array.
.BR qsort ()
´Ø¿ô¤Ï¡¢
\fInmemb\fP ¸Ä¤ÎÂ礭¤µ \fIsize\fP ¤ÎÍ×ÁǤò¤â¤ÄÇÛÎó¤òʤÙÊѤ¨¤ë¡£
\fIbase\fP °ú¤­¿ô¤ÏÇÛÎó¤ÎÀèƬ¤Ø¤Î¥Ý¥¤¥ó¥¿¤Ç¤¢¤ë¡£
.PP
.\"O The contents of the array are sorted in ascending order according to a
.\"O comparison function pointed to by \fIcompar\fP, which is called with two
.\"O arguments that point to the objects being compared.
\fIcompar\fP ¤ò¥Ý¥¤¥ó¥¿¤È¤¹¤ëÈæ³Ó´Ø¿ô¤Ë¤è¤Ã¤Æ¡¢
ÇÛÎó¤ÎÃæ¿È¤Ï¾º½ç (ÃͤÎÂ礭¤¤¤â¤Î¤Û¤É¸å¤ËʤֽçÈÖ) ¤Ëʤ٤é¤ì¤ë¡£
Èæ³Ó´Ø¿ô¤Î°ú¤­¿ô¤ÏÈæ³Ó¤µ¤ì¤ë¤Õ¤¿¤Ä¤Î¥ª¥Ö¥¸¥§¥¯¥È¤Î¥Ý¥¤¥ó¥¿¤Ç¤¢¤ë¡£
.PP
.\"O The comparison function must return an integer less than, equal to, or
.\"O greater than zero if the first argument is considered to be respectively
.\"O less than, equal to, or greater than the second.
.\"O If two members compare
.\"O as equal, their order in the sorted array is undefined.
Èæ³Ó´Ø¿ô¤Ï¡¢Âè°ì°ú¤­¿ô¤¬ÂèÆó°ú¤­¿ô¤ËÂФ·¤Æ¡¢
1) ¾®¤µ¤¤¡¢2) Åù¤·¤¤¡¢3) Â礭¤¤¤Î¤½¤ì¤¾¤ì¤Ë±þ¤¸¤Æ¡¢
1) ¥¼¥í¤è¤ê¾®¤µ¤¤À°¿ô¡¢2) ¥¼¥í¡¢3) ¥¼¥í¤è¤êÂ礭¤¤À°¿ô¤Î
¤¤¤º¤ì¤«¤òÊÖ¤µ¤Ê¤±¤ì¤Ð¤Ê¤é¤Ê¤¤¡£
Æó¤Ä¤ÎÍ×ÁǤÎÈæ³Ó·ë²Ì¤¬Åù¤·¤¤¤È¤­¡¢
ʤÙÊѤ¨¤¿¸å¤ÎÇÛÎó¤Ç¤Ï¡¢¤³¤ì¤éÆó¤Ä¤Î½ç½ø¤Ïµ¬Äꤵ¤ì¤Æ¤¤¤Ê¤¤¡£
.\"O .SH "RETURN VALUE"
.SH ÊÖ¤êÃÍ
.\"O The
.\"O .BR qsort ()
.\"O function returns no value.
.BR qsort ()
¤ÏÃͤòÊÖ¤µ¤Ê¤¤¡£
.\"O .SH "CONFORMING TO"
.SH ½àµò
SVr4, 4.3BSD, C89, C99.
.\"O .SH NOTES
.SH Ãí°Õ
.\"O Library routines suitable for use as the
.\"O .I compar
.\"O argument include
.\"O .BR alphasort (3)
.\"O and
.\"O .BR versionsort (3).
.I compar
°ú¤­¿ô¤Ë»ÈÍѤ¹¤ë¤Î¤ËŬ¤·¤Æ¤¤¤ë¥é¥¤¥Ö¥é¥ê¥ë¡¼¥Á¥ó¤È¤·¤Æ¤Ï
.BR alphasort (3),
.BR versionsort (3)
¤¬¤¢¤ë¡£
.\"O To compare C strings, the comparison function can call
.\"O .BR strcmp (3),
.\"O as shown in the example below.
C ¤Îʸ»úÎó¤òÈæ³Ó¤¹¤ë¾ì¹ç¡¢°Ê²¼¤ÎÎã¤Ë¤¢¤ë¤è¤¦¤ËÈæ³Ó´Ø¿ô¤Ç
.BR strcmp (3)
¤ò¸Æ¤Ó½Ð¤¹¤³¤È¤â¤Ç¤­¤ë¡£
.\"O .SH EXAMPLE
.SH Îã
.\"O For one example of use, see the example under
.\"O .BR bsearch (3).
»ÈÍÑÎã¤Ë¤Ä¤¤¤Æ¤Ï¡¢
.BR bsearch (3)
¤Ë¤¢¤ëÎã¤ò»²¾È¤¹¤ë¤³¤È¡£

.\"O Another example is the following program,
.\"O which sorts the strings given in its command-line arguments:
°Ê²¼¤Î¥×¥í¥°¥é¥à¤ËÊ̤λÈÍÑÎã¤ò¼¨¤¹¡£¤³¤Î¥×¥í¥°¥é¥à¤Ï¡¢
¥³¥Þ¥ó¥É¥é¥¤¥ó°ú¤­¿ô¤Ç»ØÄꤵ¤ì¤¿Ê¸»úÎó¤ÎʤӴ¹¤¨¤ò¹Ô¤¦¡£
.sp
.nf
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static int
cmpstringp(const void *p1, const void *p2)
{
.\"O     /* The actual arguments to this function are "pointers to
.\"O        pointers to char", but strcmp(3) arguments are "pointers
.\"O        to char", hence the following cast plus dereference */
    /* ¤³¤Î´Ø¿ô¤Î¼ÂºÝ¤Î°ú¤­¿ô¤Ï "char ·¿¤Ø¤Î¥Ý¥¤¥ó¥¿¤Î¥Ý¥¤¥ó¥¿" ¤À¤¬¡¢
       strcmp(3) ¤Î°ú¤­¿ô¤Ï "char ·¿¤Ø¤Î¥Ý¥¤¥ó¥¿" ¤Ç¤¢¤ë¡£
       ¤½¤³¤Ç¡¢°Ê²¼¤Î¤è¤¦¤Ë¥­¥ã¥¹¥È¤ò¤·¤Æ¤«¤é¥Ý¥¤¥ó¥¿¤ÎµÕ»²¾È¤ò¹Ô¤¦¡£*/

    return strcmp(* (char * const *) p1, * (char * const *) p2);
}

int
main(int argc, char *argv[])
{
    int j;

    if (argc < 2) {
        fprintf(stderr, "Usage: %s <string>...\\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    qsort(&argv[1], argc \- 1, sizeof(char *), cmpstringp);

    for (j = 1; j < argc; j++)
        puts(argv[j]);
    exit(EXIT_SUCCESS);
}
.fi
.\"O .SH "SEE ALSO"
.SH ´ØÏ¢¹àÌÜ
.BR sort (1),
.BR alphasort (3),
.BR strcmp (3),
.BR versionsort (3)