.\" -*- nroff -*-
.\" Copyright 1995 Yggdrasil Computing, Incorporated.
.\" written by Adam J. Richter (adam@yggdrasil.com),
.\" with typesetting help from Daniel Quinlan (quinlan@yggdrasil.com).
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.\" You should have received a copy of the GNU General Public
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.\" Modified by David A. Wheeler <dwheeler@dwheeler.com> 2000-11-28.
.\" Applied patch by Terran Melconian, aeb, 2001-12-14.
.\" Modified by Hacksaw <hacksaw@hacksaw.org> 2003-03-13.
.\"
.\" Japanese Version Copyright (c) 1998 NAKANO Takeo all rights reserved.
.\" Translated Sat May 23 1998 by NAKANO Takeo <nakano@apm.seikei.ac.jp>
.\" Updated & Modified Tue Sep 14 1999 by NAKANO Takeo 
.\"
.\" Modified Sun Mar 19 23:01:38 JST 2000
.\"         by HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Updated Fri Feb 16 JST 2001 by Kentaro Shirakata <argrath@ub32.org>
.\" Updated Fri Dec 21 JST 2001 by Kentaro Shirakata <argrath@ub32.org>
.\" Updated Wed Oct 21 JST 2002 by Kentaro Shirakata <argrath@ub32.org>
.\" Updated Mon Sep  1 JST 2003 by Kentaro Shirakata <argrath@ub32.org>
.\"
.TH DLOPEN 3 2003-03-13 "Linux" "Linux Programmer's Manual"
.SH ̾
dlclose, dlerror, dlopen, dlsym \- ʥߥå󥯤ԤؤΥץߥ󥰥󥿡ե
.SH 
.B #include <dlfcn.h>
.sp
.BI "void *dlopen(const char *" filename ", int " flag );
.br
.BI "const char *dlerror(void);"
.br
.BI "void *dlsym(void *" handle ", char *" symbol );
.br
.BI "int dlclose(void *" handle );
.sp
üʥܥ:
.BR "_init" ", " "_fini"
.SH 
.B dlopen
 NUL üʸ
.I filename
ǻꤵ줿̾Υեʥߥå饤֥Ȥƥɤ
Υʥߥå饤֥
 (opaque) ʡ֥ϥɥפ֤
.\" opaque ˤĤƤ [JM:09377] 
.I filename
Хѥ ("/" ǻϤޤѥ) \fIʤ\fPˤϡե
ʲξ꤫鸡롣
.RS
.PP
桼 \fBLD_LIBRARY_PATH\fP Ķѿǻꤵ줿ڤ
ǥ쥯ȥꥹȡ
.PP
\fI/etc/ld.so.cache\fP ˤ饤֥ꡦåΥꥹȡ
.PP
\fI/lib\fP \fI/usr/lib\fP
.RE
.PP
.I filename
 NULL ݥ󥿤Ǥϡ
֤ϥɥϥᥤץΤΤˤʤ롣
.PP
ץ󤵤줿饤֥ǤγȤϡ
Υ饤֥ΰ¸ꥹȤˤ饤֥꤫Ǥ
.B RTLD_GLOBAL
ե饰ȶ˥ץ󤵤Ƥ饤֥ѤƲ褵롣
¹ԥե뤬 "-rdynamic" ե饰ȤȤ˥󥯤Ƥϡ
¹ԥեΥХ륷ܥ⡢
ʥߥå˥ɤ饤֥ؤλȲѤ롣
.PP
.I flag
ϰʲΤ줫ǤʤФʤʤ:
.B RTLD_LAZY
ϥʥߥå饤֥Υɤ¹Ԥݤ
̤ܥ缡褷ƤȤ򼨤
.B RTLD_NOW

.B dlopen
νκǸǤ٤Ƥ̤ܥ褷줬Ǥʤˤ 
dlopen ԤȤʤ뤳Ȥ򼨤
.B RTLD_GLOBAL

.I flag
 OR 黻뤳ȤǤ롣ξˤϡ饤֥Ƥ
ܥ뤬³ƥɤ¾Υ饤֥Ǥͭˤʤ롣
.PP
饤֥꤬
.B _init
Ȥ̾Υ롼򥨥ݡȤƤС dlopen λ
Υɤ¹Ԥ롣
ξ硢ȥåץեȤΥ󥯤򤱤ɬפ롣
 gcc Υޥɥ饤 "-nostartfiles" ץꤹ뤳Ȥ
¸Ǥ롣
.PP
Ʊ饤֥꤬
.B dlopen()
ˤä٥ɤ줿ˤϡƱեϥɥ뤬֤롣
dl 饤֥ϥʥߥåեϥɥΥ󥯿ݻƤ롣
äƥʥߥå饤֥
.B dlclose

.B dlopen
ƱƤӽФʤХɤʤ
.PP
.B dlopen
ϡ餫ͳǼԤ NULL ֤
dl 롼 (dlopen, dlsym, dlclose) Τ줫
Ǥᤤ顼ϡ
.B dlerror()
ˤäƿʹ֤˲ɤʷɽ뤳ȤǤ롣
.B dlerror
Ͻ줿뤤ϺǸ˸ƤӽФ줿饨顼ä
ʤ NULL ֤ (
.B dlerror()
 2 ³ƸƤӽФȡ 2 ܤΥǤɬ NULL ֤롣)
.PP
.B dlsym
 dlopen ˤä֤줿ʥߥå饤֥Ρ֥ϥɥפȡ 
̥ʸǽü줿ʸΥܥ̾˼ꡢ
Υܥ뤬ɤƤ륢ɥ쥹֤
ܥ뤬Ĥʤˤϡ
.B dlsym
 NULL ֤
.B dlsym
Υ顼Ĵ٤ˤϡ
.B dlerror
η̤ѿ¸
줬 NULL ǤʤɤåΤǤ롣
ܥͤºݤ NULL Ǥ⤢뤫Ǥ롣ޤ
.B dlerror
η̤ѿ¸ƤȤɬפʤȤǤ롣ʤʤ⤦
.B dlerror
ƤӽФȡ֤ͤ NULL ȤʤäƤޤǤ롣
.PP
.B RTLD_DEFAULT

.B RTLD_NEXT
ȤĤ̤ʵϥɥ뤬롣
ԤϥǥեȤΥ饤֥긡Ȥäơ륷ܥ뤬
ǽ˸Ȥõ
Ԥ(ʥߥå饤֥ǤΤͭѤǤ뤬)
ǸߤΥ饤֥ʹߡ˴ؿȤõ
ˤꡢ¾ζͭ饤֥δؿؤΥåѡ󶡤Ǥ롣
.PP
.B dlclose
ϥʥߥå饤֥Υϥɥ
.I handle
λȥȤ 1 餹ȥȤ 0 ˤʤꡢ¾
ɤƤ饤֥ˤäƥܥ뤬ȤƤʤС
Υʥߥå饤֥ϥɤ롣
Υʥߥå饤֥ˤä
.B _fini
Ȥ̾Υ롼󤬥ݡȤƤˤϡ
饤֥򥢥ɤľˤΥ롼󤬸ƤӽФ롣
.SH ֤
.B dlclose
 0 ֤顼λ 0 ֤
.SH 
.B math 饤֥ɤ2.0 ;ɽ
.RS
.nf
.if t .ft CW
#include <stdio.h>
#include <dlfcn.h>

int main(int argc, char **argv) {
    void *handle;
    double (*cosine)(double);
    char *error;

    handle = dlopen ("libm.so", RTLD_LAZY);
    if (!handle) {
        fprintf (stderr, "%s\en", dlerror());
        exit(1);
    }

    cosine = dlsym(handle, "cos");
    if ((error = dlerror()) != NULL)  {
        fprintf (stderr, "%s\en", error);
        exit(1);
    }

    printf ("%f\en", (*cosine)(2.0));
    dlclose(handle);
    return 0;
}
.if t .ft P
.fi
.RE
.PP
Υץ "foo.c" ˽񤤤ȤȡʲΥޥɤǥץ
ӥɤǤ롣
.RS
.LP
gcc -rdynamic -o foo foo.c -ldl
.RE
.PP
_init()  _fini() 򥨥ݡȤ饤֥ξ
ʲΤ褦ˤƥѥ뤹ɬפ롣Ȥ bar.c 򥳥ѥ뤹:
.RS
.LP
gcc -shared -nostartfiles -o bar bar.c
.RE
.SH 
ܥ RTLD_DEFAULT  RTLD_NEXT ϡ
ͽ _GNU_SOURCE ƤΤ
.I <dlfcn.h>
롣
.SH 
dlopen 󥿡եɸ Solaris ȤˤƤ롣
.\" .SH ռ
.\" Linux  dlopen μϡ Eric Youngdale ˤäƤʤ줿
.\" ΤȤ Mitch D'Souza, David Engel, Hongjiu Lu, Andreas Schwab 
.\" Ϥä
.\" Υޥ˥奢ڡ Adam Richter 񤤤
.SH Ϣ
.BR ld (1),
.BR ld.so (8),
.BR ldconfig (8),
.BR ldd (1),
.B ld.so.info