.\" -*- 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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.\" 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 
.\"
.TH DLOPEN 3 "16 May 1995" "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 dladdr(void *"address ", Dl_info *"dlip ");"
.br
.BI "int dlclose (void *"handle ");
.sp
üʥܥ:
.BR "_init" ", " "_fini" ". "
.SH 
.B dlopen
 null üʸ
.I filename
ǻꤵ줿̾Υեʥߥå饤֥Ȥƥɤ
Υʥߥå饤֥
Ʃ (opaque) ʡ֥ϥɥפ֤
.\"?? opaque ϥɥ?
.I filename
Хѥ ("/" ǻϤޤѥ) \fIʤ\fPˤϡե
ϰʲξ꤫鸡롣
.RS
.PP
桼 \fBLD_LIBRARY\fP Ķѿǻꤵ줿ڤΥǥ
쥯ȥꥹȡ
.PP
\fI/etc/ld.so.cache\fP ˤ饤֥Υꥹȡ
.PP
\fI/usr/lib\fP  \fI/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 λˤ
Υɤ¹Ԥ롣Ʊ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 dladdr
ϡ
.I address
ǻꤵ줿֤ͭƤ붦ͭ饤֥˴ؤ֤
.B dladdr
ȥ򡢼Ԥ󥼥֤ͤ
.PP
.B dlclose
ϥʥߥå饤֥Υϥɥ
.I handle
λȥȤ 1 餹ȥȤ 0 ˤʤꡢ¾ǥɤƤ
饤֥ˤäƥܥ뤬ȤƤʤСΥʥߥå饤
֥ϥɤ롣Υʥߥå饤֥ˤä
.B _fini
Ȥ̾Υ롼󤬥ݡȤƤˤϡ
饤֥򥢥ɤľˤΥ롼󤬸ƤӽФ롣
.SH 
.B math 饤֥ɤ2.0 ;ɽ롣
.RS
.nf
.if t .ft CW
#include <dlfcn.h>

int main(int argc, char **argv) {
    void *handle = dlopen ("/lib/libm.so", RTLD_LAZY);
    double (*cosine)(double) = dlsym(handle, "cos");
    printf ("%f\\n", (*cosine)(2.0));
    dlclose(handle);
}
.if t .ft P
.fi
.PP
Υץ "foo.c" ˽񤤤ȤȡʲΥޥɤǥץ
ӥɤ뤳ȤǤ롣
.RS
.LP
gcc -rdynamic -o foo foo.c -ldl
.RE
.RE
.LP
.B ƱȤ򤷤Ƥ뤬٤Ƥʳǥ顼åԤäƤ:
.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 ("/lib/libm.so", RTLD_LAZY);
    if (!handle) {
        fputs (dlerror(), stderr);
        exit(1);
    }

    cosine = dlsym(handle, "cos");
    if ((error = dlerror()) != NULL)  {
        fputs(error, stderr);
        exit(1);
    }

    printf ("%f\\n", (*cosine)(2.0));
    dlclose(handle);
}
.if t .ft P
.fi
.RE
.SH ռ
dlopen 󥿡եɸ Solaris ȤˤƤ롣
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)