1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
3 .\" Permission is granted to make and distribute verbatim copies of this
4 .\" manual provided the copyright notice and this permission notice are
5 .\" preserved on all copies.
7 .\" Permission is granted to copy and distribute modified versions of this
8 .\" manual under the conditions for verbatim copying, provided that the
9 .\" entire resulting derived work is distributed under the terms of a
10 .\" permission notice identical to this one.
12 .\" Since the Linux kernel and libraries are constantly changing, this
13 .\" manual page may be incorrect or out-of-date. The author(s) assume no
14 .\" responsibility for errors or omissions, or for damages resulting from
15 .\" the use of the information contained herein. The author(s) may not
16 .\" have taken the same level of care in the production of this manual,
17 .\" which is licensed free of charge, as they might when working
20 .\" Formatted or processed versions of this manual, if unaccompanied by
21 .\" the source, must acknowledge the copyright and authors of this work.
23 .\" References consulted:
24 .\" Linux libc source code
25 .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
28 .\" Modified 1993-03-29, David Metcalfe
29 .\" Modified 1993-07-24, Rik Faith (faith@cs.unc.edu)
30 .\" 2006-01-15, mtk, Added example program.
32 .\" FIXME glibc 2.8 added qsort_r(), which needs to be documented.
34 .\" Japanese Version Copyright (c) 1997 YOSHINO Takashi
35 .\" all rights reserved.
36 .\" Translated 1997-01-21, YOSHINO Takashi <yoshino@civil.jcn.nihon-u.ac.jp>
37 .\" Updated & Modified 2004-06-06, Yuichi SATO <ysato444@yahoo.co.jp>
38 .\" Updated 2006-01-18, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
40 .TH QSORT 3 2009-09-15 "" "Linux Programmer's Manual"
43 .\"O qsort \- sorts an array
48 .B #include <stdlib.h>
50 .BI "void qsort(void *" base ", size_t " nmemb ", size_t " size ,
51 .BI " int(*" compar ")(const void *, const void *));"
57 .\"O function sorts an array with \fInmemb\fP elements of
59 .\"O The \fIbase\fP argument points to the start of the
63 \fInmemb\fP 個の大きさ \fIsize\fP の要素をもつ配列を並べ変える。
64 \fIbase\fP 引き数は配列の先頭へのポインタである。
66 .\"O The contents of the array are sorted in ascending order according to a
67 .\"O comparison function pointed to by \fIcompar\fP, which is called with two
68 .\"O arguments that point to the objects being compared.
69 \fIcompar\fP をポインタとする比較関数によって、
70 配列の中身は昇順 (値の大きいものほど後に並ぶ順番) に並べられる。
71 比較関数の引き数は比較されるふたつのオブジェクトのポインタである。
73 .\"O The comparison function must return an integer less than, equal to, or
74 .\"O greater than zero if the first argument is considered to be respectively
75 .\"O less than, equal to, or greater than the second.
76 .\"O If two members compare
77 .\"O as equal, their order in the sorted array is undefined.
78 比較関数は、第一引き数が第二引き数に対して、
79 1) 小さい、2) 等しい、3) 大きいのそれぞれに応じて、
80 1) ゼロより小さい整数、2) ゼロ、3) ゼロより大きい整数の
83 並べ変えた後の配列では、これら二つの順序は規定されていない。
84 .\"O .SH "RETURN VALUE"
88 .\"O function returns no value.
91 .\"O .SH "CONFORMING TO"
93 SVr4, 4.3BSD, C89, C99.
96 .\"O Library routines suitable for use as the
99 .\"O .BR alphasort (3)
101 .\"O .BR versionsort (3).
103 引き数に使用するのに適しているライブラリルーチンとしては
107 .\"O To compare C strings, the comparison function can call
109 .\"O as shown in the example below.
110 C の文字列を比較する場合、以下の例にあるように比較関数で
115 .\"O For one example of use, see the example under
116 .\"O .BR bsearch (3).
121 .\"O Another example is the following program,
122 .\"O which sorts the strings given in its command-line arguments:
123 以下のプログラムに別の使用例を示す。このプログラムは、
124 コマンドライン引き数で指定された文字列の並び換えを行う。
132 cmpstringp(const void *p1, const void *p2)
134 .\"O /* The actual arguments to this function are "pointers to
135 .\"O pointers to char", but strcmp(3) arguments are "pointers
136 .\"O to char", hence the following cast plus dereference */
137 /* この関数の実際の引き数は "char 型へのポインタのポインタ" だが、
138 strcmp(3) の引き数は "char 型へのポインタ" である。
139 そこで、以下のようにキャストをしてからポインタの逆参照を行う。*/
141 return strcmp(* (char * const *) p1, * (char * const *) p2);
145 main(int argc, char *argv[])
150 fprintf(stderr, "Usage: %s <string>...\\n", argv[0]);
154 qsort(&argv[1], argc \- 1, sizeof(char *), cmpstringp);
156 for (j = 1; j < argc; j++)