Sophie: howto-text-ja-2006-5mdv2010.0 noarch

howto-text-ja-2006-5mdv2010.0.noarch.rpm

Program Library HOWTO

David A. Wheeler

ú{êó / ìèMF

        takahiko@hakubi.co.jp
      

version 0.75, 31 October 2000

Revision History                                                       
Revision 0.75-J1                           4 Dec 2000                  

vO}pÌ±Ì HOWTO ÅÍALinux ãÅvOCuðì¬Ag
p·éû@ð_¶Ü·B±±ÉÍAÃICuA¤LCuA®IÉ
[h³êéCuAªÜÜêÜ·B

ªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªª

Table of Contents
1. Í¶ßÉ
2. ÃICu
3. ¤LCu
   
    3.1. ñ©²Æ
       
        3.1.1. ¤LCu¼
        3.1.2. t@CVXezu
       
    3.2. CuÍÇÌæ¤Égíêé©
    3.3. Â«Ï
    3.4. ¤LCuÌì¬
    3.5. ¤LCuÌCXg[Ægp
    3.6. ñÝ·Cu
   
4. ®IÉ[h³êé (Dynamically Loaded; DL) Cu
   
    4.1. dlopen()
    4.2. dlerror()
    4.3. dlsym()
    4.4. dlclose()
    4.5. DL CuÌá
   
5. G^
   
    5.1. nm R}h
    5.2. ÁÊÈÖ _init Æ _fini
    5.3. ¤LCuÍXNvg»Å«é
    5.4. GNU libtool
    5.5. É[É¬³ÈÀsÂ\t@C
   
6. ³çÉ½Ìá
   
    6.1. t@C libhello.c
    6.2. t@C libhello.h
    6.3. t@C demo_use.c
    6.4. t@C script_static
    6.5. t@C script_shared
    6.6. t@C demo_dynamic.c
    6.7. t@C script_dynamic
   
7. »Ì¼Ìîñ¹
8. ì ÆCZX

1. Í¶ßÉ

vO}Ì½ßÌ±Ì HOWTO ÍAGNU c[ZbgðgpµÄ¢é Linux
ãÅvOCuðì¬Agp·éû@ð_¶Ü·B ``vO
Cu'' ÆÍAPÉA ÆÅvOÉgÝÜêé±ÆÉÈéRpC
ÏÝÌR[h (yÑf[^) ðÜÞt@CÌ±ÆÅ·BvOCu
ÍAvOðAæèW[»µAæè¬ÄRpCÅ«Aæ
èÈPÉXVÅ«éàÌÉµÜ·BvOCuÍAOÂÌ^Cv\
\ÃICuA¤LCuA®IÉ[h³êé (dynamically
loaded; DL) Cu\\ÉªÞ·é±ÆªÅ«Ü·B

±Ì¶ÍAÅÉAÃICu\\vOªÀs³êéOÉ»ÌÀ
sÂ\vOÉgÝÜêéCu\\ÉÂ¢Ä_¶Ü·B»ê©ç
A¤LCu\\vOÀsÉ[h³êA©Â¡ÌvO
ÔÅ¤L³êéCu\\ÉÂ¢Ä_¶Ü·BÅãÉA®IÉ[h³ê
é (dynamically loaded; DL) Cu\\vOÀsÌCÓÌ_
Å[hµÄgp·é±ÆªÂ\ÈCu\\ÉÂ¢Ä_¶Ü·B DL 
CuÍAÀÛÉÍÙÈéCu`®Æ¢¤í¯ÅÍ èÜ¹ñ (ÃI
Cuà¤LCuà DL CuÆµÄgp·é±ÆªÂ\Å·)
B»ÌãíèÉAvO}ª DL CuðÇÌæ¤Égp·é©Æ¢¤
_É¨¢ÄAá¢ª èÜ·BHOWTO ÍA³çÉ½Ìáð°Ä¢éÍA»
Ì¼Ìîñ¹ÖÌQÆð°Ä¢éÍAðàÁÄI¹µÜ·B

±Ì HOWTO ÍÀsÂ\t@CÆCuÌ½ßÌ Executable and
Linking Format (ELF) `®\\ð¡ÌÙÆñÇSÄÌ Linux fBXgr
[VÅgp³êÄ¢é`®\\ÉÂ¢ÄÌÝ_¶Ü·B GNU gcc c[Z
bgÍAÀÛÉÍ ELF ÈOÌCu`®ðµ¤±ÆªÅ«Ü·BÁÉAÙ
ÆñÇÌ Linux fBXgr[VÅÍA®Ì a.out `®ð¡È¨g
p·é±ÆªÂ\Å·Bµ©µÈªçA±êçÌ`®Í±Ì¶ÌÎÛOÅ·
B

¤LCuðwµÄ dynamically linked libraries (DLL) Æ¢¤pêð
g¤lª¢é±ÆA»Ì DLL Æ¢¤pêð DL CuÆµÄgp³êéC
ÓÌCuðÓ¡·é½ßÉg¤lª¢é±ÆAÜ½AÇ¿ç©Ìðð
½·CuðÓ¡·é½ßÉ DLL Æ¢¤pêðg¤lª¢é±ÆAÉÍ
Óµ½Ù¤ªæ¢Å·B¢¸êÌÓ¡ðæèã°éÉµÄàA±Ì HOWTO Í
Linux ãÅÌ±êçSÄÌ DLL ÉÂ¢ÄJo[µÜ·B

½ÌVXeÉÚA³êéAvP[Vðì¬µÄ¢éÈçÎACu
ð\zµCXg[·éÌÉALinux c[ð¼Úgp·éãíèÉ 
GNU libtool <http://www.gnu.org/software/libtool/libtool.html> ðgp·
é±Æðl¶µ½Ù¤ªæ¢©àµêÜ¹ñBGNU libtool ÍA¤LCu
gpÌ¡G³ (á¦ÎA»êçðì¬µCXg[·éÈÇ) ðêÑ«Ì
 é|[^uÈC^[tF[XÅB·AÄpIÈCuT|[gXN
vgÅ·BLinux ãÅÍAGNU libtool Í±Ì HOWTO ÉLq³êÄ¢éc[
ÆµKÌãÉ\z³êÄ¢Ü·B®IÉ[h³êéCuÖÌ|[^
uÈC^[tF[XpÉAlXÈ|[^reBbp[ðgp·é±Æ
ªÅ«Ü·BGNU libtool ÍA ``libltdl'' ÆÄÎêé»ÌíÌbp[ðÜ
ñÅ¢Ü·B¼ÌIðÆµÄÍAÂÀ«Ì éû@Å®I[fBOðT
|[g·é glib Cu (glibc Æ¬¯µÈ¢Å¾³¢) ðgp·é±
ÆàÅ«Ü·Bglib ÉÂ¢ÄÍA http://developer.gnome.org/doc/API/glib
/glib-dynamic-loading-of-modules.html Å³çÉmé±ÆªÅ«Ü·BÄx
q×Ü·ªALinux ãÅÍA±Ì@\ÍA±Ì HOWTO àÉLq³êÄ¢é\¬
¨ðgp·é±ÆÉæÁÄÀ³êÄ¢Ü·Bàµà È½ªÀÛÉ Linux ã
ÅR[hðJAàµÍfobOµÄ¢éÈçÎA¨»çÈ¨³çÌ±Æ
A±Ì HOWTO àÌîñð~³êé±ÆÅµå¤B

±Ì HOWTO ÌêzzêÍ http://www.dwheeler.com/program-library Å
 èALinux Documentation Project (http://www.linuxdoc.org) Éñ¡³ê
Ä¢Ü·Bì Í David A. Wheeler É è (Copyright (C) 2000)A
General Public License (GPL) ÅCZX³êÄ¢Ü·B³çÈéîñÉÂ
¢ÄÍÅãÌÍðÇñÅ¾³¢B

ªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªª

2. ÃICu

ÃICuÍAÊíÌIuWFNgt@CÌPÈéWÌÅ·BµKI
ÉAÃICuÍ ``.a'' Æ¢¤g£qð¿Ü·B±ÌWÌÍAar
(archiver) vOðgpµÄì¬³êÜ·BÃICuÍÈOÙÇÉ
ÍgíêÈÈÁÄ¢Ü·ªA»êÍA¤LCuÌÙ¤ªDêÄ¢é±
ÆÉæèÜ· ( ÆÅq×Ü·)B»êÅàÜ¾AÃICuÍXì¬³
ê\\Í¶ßÍðjIÈRÅ¶ÝµÄ¢½ÌÅ·ª\\Aà¾·éÌàæè
ÈPÅ·B

[UÍAR[hðÄRpC·éKvàÈÃICuðvO
ÉN·é±ÆªÅ«AÄRpCÉ©©éÔðßñÅ«Ü·B\\
ð¡Ìæè¬ÈRpCÌ±Æðl¦êÎAÄRpCÔÍdvÅÍ
ÈÈÁÄ«Ä¢Ü·\\»Ì½ßÉ±ÌRt¯ÍÈOÙÇLÍÅÍ èÜ
¹ñBÃICuÍA»ÌJÒªACuÖN·é±Æðv
O}ÉÂÍµ½¢ªCu\[XR[hÍnµ½ÍÈ¢AÆ¢¤ê
ÉµÎµÎðÉ§¿Ü· (±êÍCux_[ÉÆÁÄÍDsÅ·
ªA»ÌCuðg¨¤ÆµÄ¢évO}ÉÆÁÄÍ¾ç©ÉDs
ÆÍ¾¦Ü¹ñ)B_IÉÍAÀsÂ\t@CÉN³êéÃI ELF 
CuàÌR[hÍá±¬ (1-5%) ®ì·éÍ¸Å·ªAÀÛÉÍA¼Ì
²¿á²¿áµ½vöÌ½ßA»ÌÊèÉÈé±ÆÍHÌæ¤Å·B

ÃICuðì¬·éAàµÍùÉ¶Ý·éÃICuÉ³çÉI
uWFNgt@CðÇÁ·éÉÍAÌæ¤ÈR}hðgpµÄ¾³¢
\\

ar rcs my_library.a file1.o file2.o                                    

±ÌR}háÅÍAÃICu my_library.a ÉIuWFNgt@C
file1.o Æ file2.o ðt¯Á¦Ä¢Ü·BÜ¾ my_library.a ª¶ÝµÄ¢È
¯êÎAì¬µÜ·BÃICuì¬ÉÖµÄ³çÉîñð¾éÉÍAar
(1) ðQÆµÄ¾³¢B

êxÃICuðì¬µÄµÜ¤ÆA»êðg¢½Èé±ÆÅµå¤B
ÀsÂ\vOðì¬·éÆ«ÉRpCÆNÌêÆµÄÄ
ÑÞ±ÆÅA¤LCuðgpÅ«Ü·BÀsÂ\t@Cðì¬·é
ÌÉ gcc(1) ðgÁÄ¢éÈçÎACuðwè·éÌÉ -l IvV
ðgpÅ«Ü·BæèÚµ¢îñÉÂ¢ÄÍ info:gcc ðQÆµÄ¾³¢B
-l Æ -L IvVðgÁÄAJ ld(1) ð¼Úgp·é±ÆàÅ«Ü·
Bµ©µÈªçAld(1) ÌC^[tF[XÍ gcc(1) æèàÏX³êâ·¢
ÌÅAÙÆñÇÌêÍ gcc(1) ðg¤Ù¤ªæ¢Å·B

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3. ¤LCu

¤LCuÍAvOªN®·éÆ«É[h³êéCuÅ·
B¤LCuªKØÉCXg[³êéÆA»ÌãÉN®³êéSÄÌ
vOÍA©®IÉ»ÌVµ¢¤LCuðg¤±ÆÉÈèÜ·BÀ
ÛÉÍA±êÈãÉÍé©É_îÅôû³êÄ¢Ü·BÆ¢¤ÌÍA Linux É
æéAv[`ÍÌ±ÆðÂ\É·é©çÅ·\\

 E CuðXVµÈªçàA»ÌCuÌÃÄãûÝ·«ÌÈ¢
    o[Wðg¢½¢Æ¢¤vOðAËRÆµÄT|[gÅ«é
   
 E ÁÊÈvOðÀs·éÆ«AÁèÌCuAàµÍCu
    àÌÁèÌÖÅ³¦I[o[ChÅ«é
   
 E ùÉ¶ÝµÄ¢éCuðgpµÄvOª®¢Ä¢éÔÉàA
    ±ÌSÄð¨±È¤±ÆªÅ«é
   
ªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªª

3.1. ñ©²Æ

±êçÌ]Üµ¢Á«·×Äð¤LCuªT|[g·é½ßÉÍA½
ÌµKÆwjÉ]íÈ¯êÎÈèÜ¹ñBCuÌ¼OAÁÉ ``soname''
Æ ``real name'' Ìá¢ÉÂ¢Ä (yÑ»êçªÇÌæ¤ÉÝìp·é©É
Â¢Ä) ð·éKvª èÜ·BÜ½A»êçªt@CVXeàÌÇÌ
êÉu©êé×«Å é©ÉÂ¢ÄàAð·éKvª èÜ·B

ªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªª

3.1.1. ¤LCu¼

SÄÌ¤LCuÍA``soname'' ÆÄÎêéÁÊÈ¼OðÁÄ¢Ü·B
soname Í ``lib'' Æ¢¤vtBbNXACuÌ¼OA``.so'' Æ¢
¤åð¿AsIhÆAC^[tF[XªÏX³êéÆ«ÉÍK¸â³
êéo[WÔªãÉ±«Ü· (ÁÊÈáOÆµÄAÅáxÌ C C
uÍ ``lib'' ÅÍnÜèÜ¹ñ) B®SÉLq³ê½ soname ÍA»Ì
Cu©gªÜÜêéfBNgðvtBbNXÆµÄÜñÅ¢Ü·B
ÀÛÌVXeÅÍA®SÉLq³ê½ soname ÍA¤LCuÌ ``real
name'' ÖÌPÈéV{bNNÉÈÁÄ¢Ü·B

SÄÌ¤LCuÍA``real name'' \\ÀÛÌCuR[hðÜÞ
t@C¼\\àÁÄ¢Ü·Breal name ÍA soname ÉAsIhA}C
i[ÔAà¤êÂsIhA[XÔAðÁ¦½àÌÅ·BÅãÌs
IhÆ[XÔÍÈÄà©Ü¢Ü¹ñB}Ci[ÔÆ[XÔÍ
AÇÌo[WÌCuªCXg[³êÄ¢é©ð³mÉ¦µAÝ
èÇÌ¯ÆÈèÜ·B±êçÌÔÍA\\»Ìæ¤É·êÎ¨ðæè
P»Å«éÉà©©íç¸\\hLgÌÅCuðà¾·éÌ
Ép¢çêÄ¢éÔÆ¯¶ÅÍÈ¢©àµêÈ¢AÆ¢¤±ÆÉÓµÄ
¾³¢B

Á¦ÄACuvÉRpCªgp·é¼OÆ¢¤àÌà èÜ·
(``linker name'' ÆÄÚ¤Æv¢Ü·) B»êÍAPÉAêØÌo[WÔ
ðæè¢½ soname Å·B

¤LCuðÇ·é®ÆÈéÌÍA±êçÌ¼OÌg¢ª¯Å·BKv
ÆÈé¤LCuÌê\ðàÉì¬·éÆ«ÉÍAvOÍAK
vÆÈé soname ðXgAbv·éÌÝÆµÜ·BtÉA¤LCuð
ì¬·éÆ«ÉÍA(æèÚ×Èo[WîñðÂ) ÁèÌt@C¼Å
Cuðì¬·éÌÝÆµÜ·BVµ¢o[WÌCuðCXg
[·éÆ«ÉÍAñAOÌÁÊÈfBNgÌ¤¿ÌêÂÉ»êðCX
g[µA»ê©ç ldconfig(8) vOðÀsµÜ·Bldconfig ÍAù
É¶Ý·ét@Cð²×Areal name ÖÌV{bNNÆµÄA
soname ðì¬µÜ·B¯lÉµÄALbVt@C /etc/ld.so.cache à
ÝèµÜ· (·®Éà¾µÜ·)B

ldconfig Í linker name ðÝèµÜ¹ñBT^IÉÍA±ÌÝèÍCu
CXg[É¨±ÈíêA``ÅVÌ'' soname àµÍÅVÌ realname
ÖÌPÈéV{bNNÆµÄAlinker name ªì¬³êÜ·BÙÆñ
ÇÌêÉ¨¢ÄACuðXVµ½çANÉ»êð©®IÉgp
µ½¢Æv¤Åµå¤©çAsoname ÖÌV{bNNÆµÄ linker
name ðìÁÄ¨±Æð¨©ßµÜ·BÍAÈº ldconfig Í©®IÉ
linker name ðÝèµÈ¢Ì©ðAH. J. Lu ÉqËÜµ½BÞÌà¾ÍAî{
IÉÍAuCuÌÅVo[WðgÁÄR[hðÀsµ½¢Ævíê
é©àmêÜ¹ñªA»¤ÅÍÈA(¨»çÝ·«ÌÈ¢) Ã¢Cu
ÉN·éJð]ñÅ¢éÆ¢¤±Æà è¤éÌÅ·vAÆ¢¤àÌÅ
µ½B»Ì½ßAldconfig ÍA È½ªÇÌCuÉvOðN
³¹½¢Ì©Æ¢¤±ÆÉÂ¢ÄÍA½Ì¼èà¨±È¢Ü¹ñBÅ·ÌÅA
JªCuÉg¤àÌðXV·é½ßÉÍACXg[ªV{
bNNð¾mÉÏXµÈ¯êÎÈçÈ¢ÌÅ·B

á¦ÎA/usr/lib/libreadline.so.3 Í®SÉLq³ê½ soname Å èA
ldconfig ª /usr/lib/libreadline.so.3.0 Æ¢¤æ¤È½ç©Ì real name
ÉÎ·éV{bNNÆµÄÝè·éàÌÅ·B /usr/lib/
libreadline.so Æ¢¤ linker name à¶Ý·é×«ÅA»êÍA /usr/lib/
libreadline.so.3 ðQÆ·éV{bNNÉÈé±ÆÅµå¤B

ªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªª

3.1.2. t@CVXezu

¤LCuÍt@CVXeÌÇ±©Ézu³êÈ¯êÎÈèÜ¹ñB
ÙÆñÇÌI[v\[X\tgEFAÍAGNU KÉ]¤Xüª èÜ·\
\Ú×Í info:standards#Directory_Variables É é info t@ChL
gð©Ä¾³¢B GNU KÍA\[XR[hðzz·éÆ«AftH
gÅÍSÄÌCuð /usr/local/lib ÉCXg[·é±Æð§µ
Ä¢Ü· (SÄÌR}hª /usr/local/bin Éüé×«¾Æà©ßÄ¢Ü·)
BÜ½A±êçÌftHgðI[o[Chµ½èACXg[[`
ðÄÑoµ½è·é½ßÌµKðÍÁ«èq×Ä¢Ü·B

t@CVXeKwK (Filesystem Hierarchy Starndard; FHS) ÍAfB
Xgr[VÉ¨¢Ä½ªÇ±ÉCXg[³êé×«©ð_¶Ä¢
Ü· (http://www.pathname.com/fhs ð©Ä¾³¢) B FHS É]¦ÎAÙÆ
ñÇÌCuÍ /usr/lib ÉCXg[³êé×«Å·ªAN®ÉKv
Æ³êéCuÍ /lib ÉA»µÄVXeÌêÉÈÁÄÍ¢È¢C
uÍ /usr/local/lib ÉCXg[³êé×«Å·B

ÀÛÉÍA±êçñÂÌ¶ÔÉµÍ èÜ¹ñBGNU KÍA\[XR[
hJÒÌ½ßÌftHgð§µÄ¢éÌÅ èAêûÅ FHS ÍAfBX
gr[^ (ÊíAVXepbP[WÇVXeðÊµÄ\[XR[h
ÌftHgðIðIÉI[o[Ch·élX) Ì½ßÌftHgð§
µÄ¢éÌÅ·BÀÛÉ±êÍ¤Ü@\µÄ¢Ü·B È½ª_E[h
µ½ ``ÅVÌ'' (¨»çoO¾ç¯Ì!) \[XR[hÍA©®IÉ©ª©
gð ``[JÈ'' fBNg (/usr/local/) ÉCXg[µÜ·B»
µÄR[hª¬nµÄ«½çApbP[WÇc[ÍAfBXgr[V
pÌWIÈÊuÉR[hðzu·é½ßÉftHgðPÉI[o[
ChÅ«Ü·B È½ÌCuªACuoRÅµ©ÄÑo³êé±
ÆÌÈ¢vOðÄÑoµÄ¢éÌÈçÎA»êçÌvOð /usr/
local/libexec ( éfBXgr[VÅÍ /usr/libexec ÉÈèÜ·)
Ézu·é×«Å·BêÂÔð¡GÉµÄ¢é±Æª ÁÄA»êÍA Red
Hat ©çh¶µ½VXeªftHgÅÍ /usr/local/lib ðCu
õÎÛÉÜßÄ¢È¢Æ¢¤±ÆÅ·B /etc/ld.so.conf ÉÖ·éºLÌc_
ð©Ä¾³¢B¼ÌWIÈCuP[VÆµÄÍAX Window
System pÌ /usr/X11R6/lib ªÜÜêÜ·B /lib/security Í PAM W[
pÉgíêÜ·ªA»êçÍÊí DL Cu (±êà ÆÅà¾µÜ·)
ÆµÄ[h³êéAÆ¢¤±ÆÉÓµÄ¾³¢B

ªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªª

3.2. CuÍÇÌæ¤Égíêé©

GNU glibc x[XÌVXe\\SÄÌ Linux VXeðÜÝÜ·\\ÅÍA
ELF oCiÀst@CðN®³¹éÆA©®IÉvO[_ª[
h³êAÀs³êÜ·B Linux VXeãÅÍA±Ì[_Í /lib/
ld-linux.so.X (X ÉÍo[WÔªüèÜ·) Æ¢¤¼OÅ·B±Ì[
_ÍAvOÉæÁÄgp³êé»Ì¼ÌSÄÌ¤LCuðT
µoµA[hµÜ·B

õÎÛÆÈéfBNgÌXgÍA/etc/ld.so.conf t@CàÉ©
êÄ¢Ü·BRed Hat ©çh¶µÄ¢éfBXgr[VÌ½ÍAÊ
í /etc/ld.so.conf t@CàÉ /usr/local/lib ðÜßÄ¢Ü¹ñBÍ±
êðoO¾Æl¦Ä¨èAÜ½A/usr/local/lib ð /etc/ld.so.conf ÉÇÁ
·é±ÆÍA Red Hat ©çh¶µÄ¢éVXeãÅ½ÌvOðç
¹é½ßÉKvÆ³êéA¤ÊÌ ``C³'' ¾ÆvÁÄ¢Ü·B

CuàÌôÂ©ÌÖðI[o[Chµ½¢¾¯ÅAcèÍ»ÌÜÜ
ÉµÄ¨«½¢ÈçÎAI[o[Ch·éCu (.o t@C) Ì¼O
ð /etc/ld.so.preload Éüêé±ÆªÅ«Ü·B±êçÌ ``æsµÄ[h
·é'' CuÍAWZbgÉæsµÜ·B±ÌæsµÄ[h·ét@
CÍAT^IÉÍÙ}pÌpb`ÆµÄgíêÜ·BfBXgr[V
ÍAÊíAzz³êéÛÉ±Ìæ¤Èt@CðÜÞ±ÆÍÈ¢Åµå¤B

vON®É±êçSÄÌfBNgðõ·éÌÍAÆÄàñø¦
IÈÌÅAÀÛÉÍLbVzuªgíêÜ·B ldconfig(8) vOÍ
ftHgÅ /etc/ld.so.conf t@CðÇÝÝAKØÈV{bN
Nð®INfBNgàÉÝèµÜ· (»Ì½ßAWÌµKÉ¤±
ÆÉÈèÜ·) B»ê©çALbVð /etc/ld.so.cache \\ ÆÅ¼Ì
vOÉgíêÜ·\\É«ÝÜ·B±êÍACuÖÌANZ
XðñíÉ¬µÜ·BÃÙIÉ¾¦é±ÆÍADLL ªÇÁ³ê½Æ«ÍK¸
AàµÍADLL ªí³ê½èA DLL fBNgÌZbgªÏ»µ½Æ«
ÉÍAldconfig ªÀs³êÈ¯êÎÈçÈ¢AÆ¢¤±ÆÅ·Bldconfig Ì
ÀsÍACuCXg[ÉpbP[WÇc[ÉæÁÄ¨±Èí
êéXebvÌêÂÅ é±Æª½¢Å·B»êÈ~AN®ÉÍA®I[
_ÍÀÛÉ /etc/ld.so.cache t@Cðg¢AKvÆ·éCuð[
hµÜ·B

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3.3. Â«Ï

lXÈÂ«Ïª±Ìèð§äÅ«Ü·BÀA±ÌèðI[o
[Ch·éÌÉg¦éÂ«Ïª¶ÝµÜ·Bá¦ÎA±ÌÁêÈÀsðA
êIÉ¼ÌCuÅãÖ·é±ÆªÅ«Ü·B Linux ÅÍAÂ«Ï
LD_LIBRARY_PATH ÍAWIÈfBNgQÉæ§ÁÄCuªõ³
êé×«fBNgQðARÅæØÁÄÀ×½àÌÅ·B±êÍAVµ
¢CuðfobOµÄ¢éÆ«âAÁÊÈÚIÌ½ßÉñWIÈC
uðgpµÄ¢éÆ«ÉÖÅ·BÂ«Ï LD_PRELOAD ÍAWZbg
ðI[o[Ch·éIuWFNgt@CðÖÆ¤ÉA¿å¤Ç /etc/
ld.so.preload Å¨±ÈíêÄ¢éæ¤ÉAñµÜ·B±êçÌ@\ÍA/
lib/ld-linux.so [_ÉæèÀ³êÄ¢Ü·B LD_LIBRARY_PATH Í½Ì
Unix CNÈVXeãÅ@\µÜ·ªASÄÌVXeãÅ®í¯ÅÍÈ
¢±ÆÉÓµÜµå¤Bá¦ÎAHP-UX Åà¯¶@\ªpÅ«Ü·ªA»
êÍ SHLIB_PATH ÆµÄÅ·µAAIX ÅÍ LIBPATH ðÊ¶ÄÆ¢¤±ÆÉÈè
Ü·BÜ½ALD_LIBRARY_PATH ÍJâeXgÉÍÖÅÍ èÜ·ªAÊí
gpÌ½ßÉCXg[ÉC³³êé×«ÅÍ èÜ¹ñB±ÌRÌà
¾ÉÂ¢ÄÍA http://www.visi.com/~barr/ldpath.html Ì ``Èº
LD_LIBRARY_PATH Í¢¯È¢Ì©'' ðQÆµÄ¾³¢B

ÀÛÉÍA[fBOèð§ä·éÂ«ÏÍÙ©Éà½³ñ¶Ý
µÜ·B»êçÌ¼OÍALD_ â RTLD_ ÅÍ¶ÜèÜ·B»êçÌÙÆñÇÍ
A[_ÌáxÈfobOâAÁê»³ê½PCpreBðÀ·
é½ßÌàÌÅ·BÙÆñÇÍA\ªÉhLg»³êÄ¢Ü¹ñB»ê
çÉÂ¢ÄméKvª éÈçÎAwK·éàÁÆàæ¢û@ÍA\[XR[
hðÇÞ±ÆÅ·B

ÁÊÈÎªÈ³êÈ¢ÈçÎA®IÉN³êéCuÉÎ·é§ä
ð[UÉFßéÆ¢¤±ÆÍAsetuid/setgid vOÉÆÁÄÍßSÈ
àÌÉÈéÅµå¤B»Ì½ßAGNU [_ÅÍAvOª setuid àµ
Í setgid ³êÄ¢éêA±êçÌÏ (yÑÞÌÏ) Í³³êé
©AàµÍA»êçªÅ«é±ÆÍåÉ§À³êÜ·B[_ÍAvO
ÌMCØ (credential) ð²×é±ÆÉæÁÄA»ÌvOª setuid
àµÍ setgid ³êÄ¢é©Ç¤©ðmFµÜ·Bàµà uid Æ euid ªÙ
Èé©AàµÍ gid Æ egid ªÙÈéÈçA[_Í»ÌvOª
setuid/setgid ³êÄ¢é (àµÍ»Ìæ¤ÈvO©çÀs³ê½)
ÆèµANðRg[·é\ÍðåÉ§ÀµÜ·B GNU
glibc CuÌ\[XR[hðÇßÎA±êÉÂ¢Ä©é±ÆªÅ«éÅ
µå¤BÁÉAelf/rtld.c t@CÆ sysdeps/generic/dl-sysdep.c t@C
ð©Ä¾³¢B±êÍAuid Æ gid ð euid Æ egid ÉµµÄ©çv
OðÄ×Î±êçÌÏª®SÉ@\·éAÆ¢¤±ÆðÓ¡µÄ¢Ü
·B»Ì¼Ì Unix CNÈVXeÍA±ÌóµðÙÈéû@Åµ¢Ü·ª
A¯¶R\\setuid/setgid vOÍÂ«ÏQÉæÁÄßxÉe¿ð
ó¯é×«ÅÍÈ¢Æ¢¤R\\ÉæèÜ·B

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3.4. ¤LCuÌì¬

¤LCuÌì¬ÍÈPÅ·BÜ¸Í¶ßÉAgcc Ì -fPIC tO (±ê
ÍA¤LCuÉKvÆ³êé ``ÊuÆ§R[h (position independent
code)'' Ì¶¬ðÂ\ÉµÜ·) ðgÁÄA¤LCuÉgÝÜêé±
ÆÉÈéIuWFNgt@Cðì¬µÜ·B»ê©çAÌ`®ðgÁÄ¤
LCuðì¬µÄ¾³¢\\

gcc -shared -Wl,-soname,your_soname \                                  
    -o library_name file_list library_list                             

ñÂÌIuWFNgt@C (a.o Æ b.o) ðì¬µA±êç¼ûðÜÞ¤L
Cuðì¬·éáð±±É°Ü·BRpCªAfobOîñ
(-g) ðÜÝAxbZ[Wð¶¬·é (-Wall) Æ¢¤±Æ\\±êçÍ¤
LCuÉKvÆÍ³êÜ¹ñª§³êÜ·\\ÉÍÓµÄ¾³¢
BRpCÍ (-c ðgÁÄ) IuWFNgt@Cð¶¬µA»µÄA
v³êé -fPIC IvVðÍÁ«èÆÜÞ±ÆÉÈèÜ·B

gcc -fPIC -g -c -Wall a.c                                              
gcc -fPIC -g -c -Wall b.c                                              
gcc -shared -Wl,-soname,libmystuff.so.1 \                              
    -o libmystuff.so.1.0.1 a.o b.o -lc                                 

Ó·×«±ÆªôÂ© èÜ·\\

 E ¶¬³ê½Cuð strip µÈ¢Å¾³¢BÜ½{ÉKvÅÈ¢
    ÀèRpCIvV -fomit-frame-pointer ðgíÈ¢Å¾³¢
    B¶¬³ê½CuÍ@\·éÅµå¤ªA±êçÌìÆÍAfob
    KðÙÆñÇg¢¨ÉÈçÈµÄµÜ¢Ü·B
   
 E R[hð¶¬·éÉÍA-fpic ÅÍÈA-fPIC ðgÁÄ¾³¢ (OÒ
    Í@\µÈ¢±Æà èÜ·BÆ¢¤ÌÍAªòªåKÍÈzu]·ðK
    vÆ·éêA-fpic Í®SÈÊuÆ§R[hð¶¬µÈ¢©àµêÈ¢
    ©çÅ·)B
   
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3.5. ¤LCuÌCXg[Ægp

êx¤LCuðì¬µÄµÜ¤ÆA»êðCXg[µ½Èé±Æ
Åµå¤BÈPÈû@ÍAWIÈfBNg (á¦Î /usr/lib ÈÇ) Ì
êÂÉA»ÌCuðRs[µAldconfig(8) ðÀs·é±ÆÅ·B

àµà±êªÅ«È¢ÈçÎ (á¦ÎA È½ª /usr/lib ðÏX·é ð
ÁÄ¢È¢ÈÇ)AÔð§ä·é½ßÉÂ«Ïðgp·é±ÆªÅ«Ü·
BÜ¸Í¶ßÉAÇ±©É¤LCuðì¬·éKvª éÅµå¤B»
ê©çAKvÈV{bNNAÁÉ soname ©ç real name ÖÌV{
bNN (¯lÉAo[WÔðÜÁ½wèµÈ¢[UÌ½ßÉ
Ao[WÔÌÈ¢ soname AÂÜèA``.so'' ÅIíé soname ©çÌ
V{bNNà) Ýè·éKvª éÅµå¤BàÁÆàÈPÈû@Í
AÌR}hCðÀs·é±ÆÅ·\\

 ldconfig -n directory_with_shared_libraries                           

»ê©çALD_LIBRARY_PATH \\¢ÂàÌêæèàæÉ¤LCuÌ
õÎÛÆÈéfBNgÌXgðRÅæØÁ½àÌ\\ðÝèµÜ·
Bbash ð¨g¢Åµ½çAÌû@Å my_program ðÀsÅ«Ü·B

LD_LIBRARY_PATH=.:$LD_LIBRARY_PATH  my_program                         

ôÂ©ÌIð³ê½ÖðI[o[Chµ½¢¾¯ÈçÎAI[o[Ch
·éIuWFNgt@Cðì¬µÄ LD_PRELOAD ðÝè·é¾¯ÅÂ\Å·
B±ÌIuWFNgt@CàÌÖÍAÎÛÆÈÁÄ¢éÖ¾¯ðI[o
[ChµÜ·B

iÍASz·éKvàÈCuðXVÅ«Ü·Bàµà API ÌÏXª
 éÈçÎACuì¬ÒÍ soname ðÏX·éÅµå¤Bµ©µÈªç
Aàµà¯¶ soname ÌÜÜÌCuÉÎ·éXVÂÉ¨¢ÄA év
OªfµÄµÜ¤æ¤ÈçAÃ¢CuðÇ±©ÉRs[µA»
ÌvOÌ¼OðÏX·é±ÆÉæÁÄ (Ã¢¼OÉ ``.orig'' ðt¯«
·ÈÇ) A§IÉÃ¢Cuo[Wðg¤±ÆªÅ«Ü·Bgp·
éCuðÄÝèµAÀÛÉÀs·é (¼OðÏX³ê½) vOð
ÄÑo·½ßÌ¬³È ``bp['' XNvgàì¬µÄ¾³¢BÔt
¯ÌµKÍA¯êfBNgàÉ¡Ìo[Wª¶Ý·é±ÆðÂ\É
µÄ¢Ü·ªA¨]ÝÈçAÃ¢Cuð»êÆ©ÌÁÊÈêÉu±
ÆàÅ«Ü·Bbp[XNvgÍAÌæ¤ÈàÌÉÈéÅµå¤\\

  #!/bin/sh                                                            
  export LD_LIBRARY_PATH=/usr/local/my_lib:$LD_LIBRARY_PATH            
  exec /usr/bin/my_program.orig $*                                     

ldd(1) ðg¦ÎA évOÉæÁÄgp³êÄ¢é¤LCuÌ
Xgð²×é±ÆªÅ«Ü·Bá¦ÎAÌæ¤É^Cv·êÎA ls ÉæÁ
Ägp³êÄ¢é¤LCuðmF·é±ÆªÅ«Ü·\\

  ldd /bin/ls                                                          

êÊIÉÍAvOÌË¶·é soname ÌXgªA¼OðãÌfB
Ng¼Æ¤É¾çêÜ·BÀÛÉÍSÄÌêÉ¨¢ÄAÈÆàñÂÌ
Ë¶vfð©é±ÆÉÈéÅµå¤\\

 E /lib/ld-linux.so.N (N ÍA1 ©»êÈãB½¢Ä¢ÍÈÆà 2) B
    ±êÍA¼ÌSÄÌCuð[h·é½ßÌCuÅ·B
   
 E libc.so.N (N ÍA6 ©»êÈã) B±êÍ C CuÅ·B¼Ì¾ê
    Å³¦AC Cuðgp·éXüª èÜ· (ÈÆà»êç©g
    ÌCuðÀ·é½ßÉ) B»Ì½ßAÙÆñÇÌvOÍ
    ÈÆà±ÌCuÍÜñÅ¢Ü·B
   
Ó\\MpÅ«È¢vOÉÎµÄ ldd ðÀsµÄÍ¢¯Ü¹ñB±ê
ÉÂ¢ÄÍA ldd(1) Ì}jAÅ¾mÉq×çêÄ¢Ü·B ldd ÍAY
vOð¼ÚÄÑo·±ÆÅ@\µÄ¢Ü·BMpÅ«È¢vOª
\úµÄ¢È¢R[hðÀsµÄµÜ¤±Æª è¦Ü·B

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3.6. ñÝ·Cu

Vµ¢o[WÌCuªÃ¢àÌÆoCiñÝ·Å éÆ«ÍA
soname ðÏX·éKvª èÜ·BC É¨¢ÄÍACuªoCiÝ·
ÅÍÈÈÁÄµÜ¤lÂÌî{IÈRª èÜ·B

 1. ³ÌdlÉKµÈ¢æ¤ÉÖÌ®ìªÏX³êÄµÜ¤
   
 2. GNX|[g³êéf[^ÚªÏX³êÄµÜ¤ (áO\\\¢Ìª
    CuàÅÌÝAP[g³êéêÉÀèA\¢ÌÌöÉCÓÌ
    ÚðÇÁ·éÌÍâèÈ¢)
   
 3. GNX|[g³êÄ¢éÖªí³êÄµÜ¤
   
 4. GNX|[g³êÄ¢éÖÌC^[tF[XªÏX³êÄµÜ¤
   
±êçÌRðñðÅ«éÈçÎACuðoCiÝ·ÉÛÂ±ÆªÅ
«Ü·BÊÌ¾¢ûð·éÆA±êçÌÏXðð¯êÎAApplication Binary
Interface (ABI) Ý·ðÛÂ±ÆªÅ«éAÆ¢¤±ÆÅ·Bá¦ÎAVµ¢
ÖðÇÁµ½¢¯êÇàÃ¢Öðíµ½ÍÈ¢©àµêÜ¹ñB\¢
ÌÌöÉÌÝACeðÇÁµACuÉ¾¯»Ì\¢ÌðAP[g
·é±ÆðÂµ (AvP[VÉÍÂµÈ¢)A»ÌÇÁÌACeð
IvVµ¢É·é (àµÍCuª»êçð½·æ¤É·é)AÈ
ÇÌìð¨±ÈÁÄ¶¶½ÏXªAÃ¢vOÉÎµÄe¿ð^¦È¢
±ÆðmFÅ«éêÉÌÝAACeðÇÁ·é±ÆªÅ«Ü·BCðt¯
Ä¾³¢Bàµà[Uª\¢ÌðzñÅgÁÄ¢éÈçÎA»Ì\¢ÌÍ
g£Å«Ü¹ñB

C++ (¨æÑARpCÏÝgÝev[gÂ^ÍRpCÏÝÌ
fBXpb`³êé\bhðT|[g·é»Ì¼Ì¾ê) ÅÍAóµÍæè
¡GÉÈèÜ·BãLÌâè_SÄªKp³êéãA³çÉ½Ìâèª è
Ü·BRÍAôÂ©ÌîñªRpC³ê½R[hàÉ ``B³ê½óÔÅ
'' À³êÄ¢éÆ¢¤±ÆÉ éÌÅ·ªA±Ì±ÆªA C++ ªêÊIÉ
ÇÌæ¤ÉÀ³êÄ¢é©ðmçÈ¢lÉÍæª©çÈ¢æ¤ÈË¶âè
ðø«N±µÄµÜ¤ÌÅ·B³mÉ¾¦ÎA»êçÍ ``Vµ¢'' âèÅÍ
 èÜ¹ñBPÉARpCÏÝÌ C++ ÌR[hªA È½ðÁ©¹é±Æ
ÉÈé©àµêÈ¢û@Å»êçÌâèðø«N±·Æ¢¤±ÆÈÌÅ·B
ÌàÌÍAoCiÝ·ðÛ·é½ßÉ C++ àÅâÁÄÍ¢¯È¢ÚÌ
Xg (¨»çs®SÅ·ª) Å èA Troll Tech eNjJ FAQ <http://
www.trolltech.com/developer/faq/tech.html#bincomp> Éæèñ³êÄ¢é
àÌÅ·B

 1. oÖðÄÀµ½àÌðÇÁ·é (Ã¢oCiª³ÌÀðÄÑ
    o·ÌªÀSÅÍÈ¢ê)BÆ¢¤ÌÍARpCÍ SuperClass::
    virtualFunction() ÄoµðRpCÉ]¿·é©çÅ· (N
    ÅÍ èÜ¹ñ)B
   
 2. ¼zoÖðÇÁÜ½Íí·éBÆ¢¤ÌÍA±ÌìÆÍSTuN
    XÌ¼zÖe[uÌTCYÆzuðÏX·é¾ë¤©çÅ·B
   
 3. CCoÖoRÅANZX³ê¤éf[^oÌ^CvðÏ
    Xµ½èAÜ½Í»êçðÚ®³¹½è·éB
   
 4. NXKwðÏX·éB½¾µA[t (óFºÊNXð½È¢N
    X) ÌVKÇÁðB
   
 5. private f[^oðÇÁÜ½Íí·éBÆ¢¤ÌÍA±ÌìÆÍS
    TuNXÌTCYÆzuðÏX·é¾ë¤©çÅ·B
   
 6. public àµÍ protected oÖªCCÖÅÈ¢êÉA
    »êçðí·éB
   
 7. public àµÍ protected oÖðCC»·éB
   
 8. CCÖª¨±ÈÁÄ¢½±ÆðÏX·éB½¾µAÃ¢o[W
    ª®ìµ±¯Ä¢éêðB
   
 9. |[^uÈvOÌoÖÌANZX  (·Èí¿A public,
    protected Ü½Í private) ðÏX·éBÆ¢¤ÌÍAANZX ðÖ
    ¼ÉµñÅµÜ¤RpCà¶Ý·é©çÅ·B
   
C++ CuÌJÒÍA±Ì·Á½çµ¢XgðèÉµÄAoCiÝ
·«ðÈ·±ÆÉÈÁÄµÜ¤ÜÌXVìÆÈãÌ±ÆðÁÉl¶µÈ¯
êÎÈèÜ¹ñBK¢ÉµÄAUnix CNÈVXe (Linux ðÜÝÜ·) Å
ÍêÂÌCuÌ¡Ìo[Wð¯É[h·é±ÆªÅ«éÌÅ
AfBXNXy[Xð¸¤±ÆÉÍÈèÜ·ªA[UÍÃ¢CuðK
vÆ·é ``Ã¢'' vOð»ÌãàÀs·é±ÆªÂ\ÅÍ èÜ·B

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4. ®IÉ[h³êé (Dynamically Loaded; DL) Cu

®IÉ[h³êé (dynamically loaded; DL) CuÍAvOÌ
N®ÈOÌÆ«É[h³êéCuÅ·B±êÍvOCâW
[ðÀ·éÌÉÁÉðÉ§¿Ü·BÆ¢¤ÌÍAvOCªKvÉÈé
ÜÅA»êð[h·éÌðÒÂ±ÆªÅ«é©çÅ·Bá¦ÎA Pluggable
Authentication Modules (PAM) VXeÍAÇÒªFØÌÝèâÄÝèð¨
±È¦éæ¤É·é½ßA DL CuðgpµÄ¢Ü·BÜ½ASÌð~
ßé±ÆÈAø¦ðã°éÚIÅA»ÌXÅR[hð}VR[hÉR
pCµA»ÌRpCãÌàÌðgp·éÆ¢¤C^v^ðÀ·é
ÌÉàðÉ§¿Ü·B±Ìû@ÍAWXgC^CRpCâA}`
[U_W (multi-user dungeon; MUD) ÌÀÉàðÉ§¿Ü·B

Linux ÅÍAÀÛÌÆ±ëADL CuÍ`®Æ¢¤_É¨¢ÄÍÁÊÅÍ
 èÜ¹ñB»êçÍAWIÈIuWFNgt@CAàµÍ¡ÜÅÉq
×½æ¤ÈWIÈ¤LCuÆµÄ\z³êÄ¢Ü·BåÈá¢ÍA
CuªAvOÌNâN®É©®IÉÍ[h³êÈ¢AÆ
¢¤_Å·B»ÌãíèACuðI[vµAV{ðõµAG
[ðµACuðÂ¶éAÆ¢¤ API Í¶ÝµÜ·B±Ì API ðg
¤½ßÉÍA C [UÍwb_t@C <dlfcn.h> ðCN[h·éKv
ª èÜ·B

Linux ÉæÁÄgp³êéC^[tF[XÍ{¿IÉ Solaris ãÌàÌÆ¯
¶ÅAª ``dlopen()'' API ÆÄÚ¤ÆµÄ¢éàÌÅ·Bµ©µÈªçA
±Ì¯¶C^[tF[XÍSÄÌvbgtH[ÅT|[g³êÄ¢éí
¯ÅÍ èÜ¹ñBHP-UX Í shl_load() Æ¢¤ÙÈé@\ðp¢Ü·µA
Windows vbgtH[Í®SÉÙÈéC^[tF[XÌ DLL ðgpµÜ
·B È½ÌÅIÚWªLÍÈ|[^reBÈçÎA¨»çAvbgt
H[ÔÌ·áðB·bsOCuÌgpðl¦½Ù¤ªæ¢Åµå
¤BêÂÌAv[`ÍAW[Ì®I[fBOðT|[g·é glib
CuÅ·B±êÍAvbgtH[ÅyäÆÈÁÄ¢é®I[fB
Op[`ðg¢A»êçÌ@\ÖÌ|[^uÈC^[tF[XðÀ
µÜ·Bglib ÉÂ¢ÄÍA http://developer.gnome.org/doc/API/glib/
glib-dynamic-loading-of-modules.html ðQÆµÄ¾³¢B glib ÌC^
[tF[XÍ»ÌhLgÌÅ\ªÉà¾³êÄ¢éÌÅA±±ÅÍ±
êÈãÍq×Ü¹ñBà¤êÂÌAv[`ÍAlibltdl ðg¤±ÆÅ·B±
êÍA GNU libtool <http://www.gnu.org/software/libtool/libtool.html>
ÌêÅ·BàÁÆ½Ì@\ð]ÞÈçÎA CORBA Object Request Broker
(ORB) ð²×ÄÝéÌàæ¢Åµå¤B Linux Æ Solaris ÅT|[g³êé
C^[tF[Xð¼Úg¤±ÆÉËRÆµÄ»¡ð¨¿ÈçÎAÇÝiñ
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4.1. dlopen()

dlopen(3) ÖÍACuðI[vµAgp·é½ßÌõðµÜ·B
C ÅÍA»Ìvg^CvÍÌæ¤ÉÈèÜ·\\

  void * dlopen(const char *filename, int flag);                       

t@C¼ª ``/'' ÅÍ¶ÜéÈçÎ (ÂÜèâÎpXÈçÎ) A dlopen()
ÍCuðõµÜ¹ñB»¤ÅÈ¢ÈçÎAdlopen() ÍÌÅC
uðõµÜ·\\

 1. [UÌ LD_LIBRARY_PATH Â«ÏàÌRÅæØçê½fBNg
    Xg
   
 2. /etc/ld.so.cache Éwè³ê½CuXg
   
 3. /usr/lib, ª /lib
   
dlopen() ÅÍAflag ÌlÍARTLD_LAZY \\``®ICuÌR[hªÀ
s³êéÆ«ÉA¢è`V{ðð¹æ'' Æ¢¤Ó¡Å·\\AàµÍ
ARTLD_NOW \\``dlopen() ª^[·éOÉSÄÌ¢è`V{ðð
¹æA»êªÅ«È¢æ¤ÈçÎ¸s¹æ'' Æ¢¤Ó¡Å·\\AÌÇ¿ç©
ÅÈ¯êÎ¢¯Ü¹ñBRTLD_GLOBAL ÍA flag ÌÇ¿ç©ÌlÆCÓÉ_
a³êéàÌÅA±¯ÄCuð[h·é±ÆÉæèCuà
Åè`³êÄ¢éOV{ð¾çêéAÆ¢¤±ÆðÓ¡µÄ¢Ü·Bf
obOÍA¨»ç RTLD_NOW ðg¢½ÈéÅµå¤BRTLD_LAZY ðg¤
ÆAð³êÈ¢QÆª Á½Æ«ÉsÂðÈG[ª¶¬³êÜ·B
RTLD_NOW ðg¤ÆACuÌI[vÉÍá±Ôª½©©éæ¤ÉÈ
èÜ· (µ©µAÌ¿Ì¿ÌõXs[hÍ¬ÈèÜ·) B±Ì±Æª[
UC^[tF[XÌâèÉÈéæ¤Åµ½çA ÆÅ RTLD_LAZY É©¦é±
ÆªÅ«Ü·B

Cuª¨Ý¢ÉË¶µÄ¢éæ¤Èç (á¦ÎAX ª Y ÉË¶µÄ¢
é) AË¶³êÄ¢éÙ¤ðæÉ[hµÄ¾³¢ (±ÌáÅ¾¦ÎAY ð
æÉ[hµA»ê©ç X ð[hµÜ·) B

dlopen() ÌßèlÍA¼Ì DL Cu[`Ågp³êé ``nh
'' \\»ÌÀÌÍBÁ³êéØ«àÌÆl¦çêÄ¢é\\Å·B[hÌ
Ýª¬÷µÈ¢êAdlopen() Í NULL ðÔµÜ·ÌÅA±Ìlð`FbN·
éKvª èÜ·B¯¶Cuª dlopen() ÅññÈã[h³êéÆA
¯¶t@CnhªÔ³êÜ·B

àµàCuª _init Æ¢¤¼OÌ[`ðGNX|[gµÄ¢êÎA
»ÌR[hÍ dlopen() ªßéOÉÀs³êÜ·B È½ÌCuÅàA
ú»[`ðÀ·é½ßÉ±êðg¤±ÆªÅ«Ü·BÚ×Í Section
5.2 ðQÆµÄ¾³¢B

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4.2. dlerror()

dlerror() ðÄ×ÎAG[ðñÅ«Ü·Bdlerror() ÍA dlopen(),
dlsym() àµÍ dlclose() ÌÅãÌÄoµÉæéG[ÉÂ¢ÄLqµÄ 
é¶ñðÔµÜ·BêÂÏíÁÄ¢éÌÍAdlerror() ðÄÑo·ÆAÈ~
Ì dlerror() ÌÄoµÍAÙ©ÌG[ª¶·éÜÅ NULL ðÔ·Æ¢¤_
Å·B

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4.3. dlsym()

DL Cuªg¦È¯êÎA»êð[hµÄàÓ¡ª èÜ¹ñB DL 
Cuðg¤½ßÌåÆÈé[`ÍAdlsym(3) Å·B±êÍA^¦çê
½ (I[vÏÝÌ) CuàÉ éV{Ìlðõ·éàÌÅ·B
±ÌÖÍÌæ¤Éè`³êÜ·\\

 void * dlsym(void *handle, char *symbol);                             

handle Í dlopen ÅÔ³ê½lÅAsymbol Ík¶ÅI[³ê½¶ñÅ
·BñðÂ\ÈçÎAdlsym() ÌÊð void* |C^Éi[µÈ¢Å¾³
¢BÆ¢¤ÌÍA»êðp·é½ÑÉLXgµÈ¯êÎ¢¯ÈÈé©ç
Å· (vOðeiXµæ¤ÆµÄ¢él½¿ÉAæèÈ¢îñ
µ©^¦È¢±ÆÉàÈèÜ·) B

dlsym() ÍAV{ª©Â©çÈ¯êÎ NULL Æ¢¤ÊðÔµÜ·BV
{ª NULL àµÍ[Æ¢¤lðÆé±ÆÍ è¦È¢Æª©ÁÄ¢êÎ
A»êÅ\¢Ü¹ñBµ©µA»¤ÅÈ¢êÍöÝIÉB³ªcèÜ·B
àµà NULL ðó¯æÁ½êA»êÍA»ñÈV{Í¶ÝµÈ¢Æ¢¤
±ÆðÓ¡·éÌÅµå¤©AàµÍ»ÌV{Ìlª NULL Å é±Æ
ðÓ¡·éÌÅµå¤©? WIÈðÍAdlerror() ðÍ¶ßÉÄÑ (¶Ý
µÄ¢é©àµêÈ¢G[ððNA·é½ßÅ·)A»ê©çV{ð
v·é½ßÉ dlsym() ðÄÑAG[ª¶µÄ¢é©Ç¤©ð²×é½ß
ÉÄx dlerror() ðÄÑo·±ÆÅ·BR[hÌfÐÍÌæ¤ÉÈéÅµå
¤\\

 dlerror(); /* G[ðNA·é */                                   
 s = (actual_type) dlsym(handle, symbol_being_searched_for);           
 if ((err = dlerror()) != NULL) {                                      
  /* nhG[BV{ð©Â¯çêÈ©Á½ */                   
 } else {                                                              
  /* V{ª©Â©Á½B»ÌlÍ s Éi[³êÄ¢é */              
 }                                                                     

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4.4. dlclose()

dlopen() Ìtª dlclose() ÅA±êÍ DL CuðN[YµÜ·B dl
CuÍ®IÈt@CnhÖÌNðÇµÄ¢éÌÅA¯ê
®ICuÉÎµÄAdlopen ª¬÷µ½ñÆ¯¶Ì dlclose ªÄÎ
êÈ¢ÀèAYCuÍÀÛÉÍã©çí³êÜ¹ñB»Ì½
ßA¯¶vOª¯¶Cuð½ñ[hµÄàAâèÉÍÈèÜ¹
ñBCuÌÄªð³êéêÍA(àµà¶Ý·éÈçÎ) _fini
ÖªÄÎêÜ·BÚ×Í Section 5.2 ðQÆµÄ¾³¢B

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4.5. DL CuÌá

dlopen(3) Ì man y[W©çÌáð±±ÉÚ¹Ü·B±ÌáÍAwCu
ð[hµA2.0 ÌRTCðoÍµAÜ½ASÄÌXebvÅG[ð`
FbNµÄ¢Ü· (§³êÄ¢Ü·) \\

     #include                                                          
    #include                                                           
                                                                       
    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);                                               
    }                                                                  

±ÌvOª "foo.c" Æ¢¤¼OÌt@C¾Æ·éÆAÌR}hÅ
vOðì¬·é±ÆªÅ«Ü·B

    gcc -Wl,export-dynamic -o foo foo.c -ldl                           

``-Wl,export-dynamic'' IvVÍÀÛÉÍKv èÜ¹ñªAXðÉ§
Â±Æª èÜ·Bld(1) ÅÌæ¤É¾L³êÄ¢Ü·\\``ELF t@C
ðì¬µÄ¢éÆ«A±ÌIvVªASÄÌV{ð®IV{e[
uÉÁ¦Ü·BÊíA®IV{e[uÍ®IIuWFNgÉæÁÄg
íêéV{¾¯ðÜñÅ¢Ü·B±ÌIvVÍ dlopen ÌgpÌ½ß
ÉKvÆÈèÜ·'' Linux VXe¾¯ÅìÆðµÄ¢éÈçÎA
``-Wl,export-dynamic'' Ì©íèÉ ``-rdynamic'' ðg¦é¯êÇàAELF
hLgÉæêÎAñ Linux VXeãÌ gcc ÅÍ ``-rdynamic'' t
OÍK¸µà@\µÈ¢AÆ¢¤±ÆÉÍÓµÄ¨¢Ä¾³¢B

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5. G^

5.1. nm R}h

nm(1) R}hÍA^¦çê½CuàÌV{ÌXgðñµÜ·
BÃICuA¤LCuÌÇ¿çÉÎµÄà@\µÜ·B nm(1) Í
^¦çê½CuÅè`³êÄ¢éV{¼AV{ÌlAV{
Ì^Cvð\¦µÜ·BÜ½A»ÌCuàÉîñª¶Ý·éÈçÎ (-l
IvVð©Ä¾³¢) AV{ª\[XR[hàÌÇ±Å (t@C
¼ÆsÔ) è`³êÄ¢é©Æ¢¤±ÆàÁèÅ«Ü·B

V{^CvÉÂ¢ÄÍà¤µà¾ªKvÅ·B^CvÍê¶Å\¦³
êÜ·B¬¶Í»ÌV{ª[JÅ é±ÆðÓ¡µAå¶Í»Ì
V{ªO[o (O) Å é±ÆðÓ¡µÜ·BT^IÈV{Ì
^CvÍÌàÌðÜÝÜ·\\ T (R[hZNVàÌÊÌè`) D (
ú»³ê½f[^ZNV) B (ú»³êÄ¢È¢f[^ZNV) U
(¢è`BV{ÍCuÉæÁÄgíêÄ¢éªACuàÅÍè
`³êÄ¢È¢) W (weak. àµà¼ÌCuà±ÌV{ðè`µÄ¢
½êA»Ìè`ªI[o[Ch·é)

ÖÌ¼OÍo¦Ä¢é¯êÇàA»êªÇÌCuÅè`³êÄ¢é©
³mÉÍv¢o¹È¢êACu¼ð©Â¯é½ßAnm Ì ``-o'' Iv
V (eCÌt@C¼ÌOÉu«Ü·) É grep ð±¯Äg¤±Æª
Å«Ü·B Bourne VFÅ êÎA/lib, /usr/lib, /usr/lib Ì¼ºÌTu
fBNgA¨æÑ /usr/local/lib àÌSCuðÎÛÉµÄ
``cos'' ðõ·éÉÍAÌæ¤ÉµÜ·\\

nm -o /lib/* /usr/lib/* /usr/lib/*/* \                                 
      /usr/local/lib/* 2> /dev/null | grep 'cos$'                      

nm ÉÖ·éàÁÆ½ÌîñÍA info:binutils#nm É[JÉCXg[
³êÄ¢é nm Ì ``info'' hLgÅ¾çêÜ·B

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5.2. ÁÊÈÖ _init Æ _fini

ñÂÌÁÊÈÖ _init Æ _fini ÍAW[ÌúÆI¹ðx
µÜ·BàµàCuàÅÖ ``_init'' ªGNX|[g³êÄ¢éÆ
A»ÌCuÌI[vÉ dlopen() ªÄÎêé½ÑA»ÌÖªÄÑ
o³êÜ·B C ÌvOÅÍA_init Æ¢¤¼OÌÖðè`·é±Æð
Ó¡µÜ·B±êÉÎ·é _fini ÆÄÎêéÖà¶ÝµA±êÍANC
AgªCuÌðúÉ dlclose() ðÄÔ½ÑÉAÄÑo³êÜ· (»
µÄðú³êÜ·) B±êçÌÖÌ C vg^CvÍÌæ¤ÉÈÁÄ¢Ü
·B

  void _init(void);                                                    
  void _fini(void);                                                    

Gcc Åt@Cð ``.o'' t@CÖÆRpC·éÆ«ÍAYê¸É
``-nostartfiles'' IvVðt¯Ä¾³¢B±ÌIvVÍAC R
pCª .so t@CÉÎµÄVXeX^[gAbvCuðNµ
È¢æ¤ÉµÜ·B±ÌIvVðt¯È¢ÆA``multiple-definition''
(d¡è`) G[ÉÈÁÄµÜ¢Ü·B _init Æ _fini ÉÖ·éc_ðÁ¦
é±ÆðñÄµÄê½±ÆA¨æÑ»Ìì¬ðè`ÁÄê½±ÆÉÎµÄ
A Jim Mischel Æ Tim Gentry É´ÓµÜ·B

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5.3. ¤LCuÍXNvg»Å«é

ÊíÌCu`®ÌãíèÉAÁêÈXNvg¾êðgÁÄ¢éeLX
gt@Cð¤LCuÆµÄ GNU [_ªFßé±ÆÍAÚÉlµÜ
·B±êÍA¼ÌCuðÔÚIÉ³¹éÌÉð§¿Ü·Bá¦ÎA
ÌÂ éêÂÌVXeãÌ /usr/lib/libc.so ðXeBOµ½àÌ
ÍÌæ¤ÉÈèÜ·B

/* GNU ld XNvg                                                   
   ¤LCuðg¤ªAôÂ©ÌÖÍÃICuàÉµ©        
   ¶ÝµÈ¢B»Ì½ßAñÔÚÉÝéB */                           
GROUP ( /lib/libc.so.6 /usr/lib/libc_nonshared.a )                     

±êÉÖ·éæèÚµ¢îñÍAld JXNvg (ld R}h¾ê) É
Â¢ÄÌ texinfo hLgðQÆµÄ¾³¢BêÊIÈîñÍAinfo:
ld#Options Æ info:ld#Commands É èAæg¤R}hÍ info:ld#
Option Commands Åà¾³êÄ¢Ü·B

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5.4. GNU libtool

½ÌVXeÉÚA³êéAvP[Vðì¬µÄ¢éÈçÎACu
ð\zµCXg[·éÌÉA GNU libtool <http://www.gnu.org/
software/libtool/libtool.html> ðgp·é±Æðl¶µ½Ù¤ªæ¢©àµ
êÜ¹ñB GNU libtool ÍAÄpIÈCuT|[gXNvgÅ·B
Libtool ÍA¤LCugpÌ¡G³ðêÑ«Ì é|[^uÈC^
[tF[XÅBµÜ·BLibtool ÍAIuWFNgì¬ACuÌN
(ÃI¨æÑ¤L) AÀsÂ\t@CÌNAÀsÂ\t@CÌfobO
ACuÌCXg[AÀsÂ\t@CÌCXg[AÉÂ¢Ä|
[^uÈC^[tF[XðñµÜ·BÜ½AvOð®IÉ[h
·é½ßÌ|[^reBbp[Å é libltdl àÜñÅ¢Ü·BæèÚ×
ÈîñÍA http://www.gnu.org/software/libtool/manual.html ðQÆµÄ
¾³¢B

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5.5. É[É¬³ÈÀsÂ\t@C

u{É¬³È Linux p ELF ÀsÂ\t@Cì¬ÉÖ·éQ½¾µ¢`
[gAv <http://www.muppetlabs.com/~breadbox/software/tiny/
teensy.html> Æ¢¤¶ªAæ¢QlÆÈéÅµå¤B±êÍA{É¬³È
ÀsÂ\vOðì¬·éû@ÉÂ¢Ä_¶Ä¢Ü·B¦¼É¾¦ÎAê
ÊIÈÂ«ÅÍA±êçÌgbNÌÙÆñÇÍg¤×«ÅÍ èÜ¹ñªA
»êçÍAELF ªÀÛÉÇÌæ¤É@\·é©ð¦µÄ¢éÆ¢¤_É¨¢Ä
AÉßÄLvÅ·B

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6. ³çÉ½Ìá

ºLÉASOÂÌAv[` (ÃIA¤LA¨æÑ®IÉ[h³êéCu
) Ìáð³çÉ°Ü·Bt@C libhello.c Í½}ÈCuÅA
wb_t@CÆµÄ libhello.h ð¿Ü·Bt@C demo_use.c ÍA»
ÌCuÌ½}ÈÄoµÅ·BÃICuâ®ICuÆµÄ
YCuðg¤û@ð¦·½ßARgt«ÌXNvg
(script_static Æ script_dynamic) ª ÆÉ±«Ü·B³çÉ
demo_dynamic.c Æ script_dynamic ª ÆÉ±«Ü·B±êçÍ¤LCu
ð®IÉ[h³êéCuÆµÄg¤û@ð¦µÜ·B

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6.1. t@C libhello.c

/* libhello.c - CugpÌÀá */                                
                                                                       
#include                                                               
                                                                       
void hello(void) {                                                     
  printf("Hello, library world.\n");                                   
}                                                                      

ªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªª

6.2. t@C libhello.h

/* libhello.h - CugpÌÀá */                                
                                                                       
                                                                       
void hello(void);                                                      

ªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªª

6.3. t@C demo_use.c

/* demo_use.c -- "hello" [`ð¼Úgp·éÀá */                 
                                                                       
#include "libhello.h"                                                  
                                                                       
int main(void) {                                                       
 hello();                                                              
 return 0;                                                             
}                                                                      

ªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªª

6.4. t@C script_static

#!/bin/sh                                                              
# ÃICuÌÀá                                                 
                                                                       
# ÃICuÌIuWFNg libhello-static.o ðì¬µÜ·B        
# ÃICuÆ®ICuÌáð¾mÉæÊ·é½ßA             
# libhello-static Æ¢¤¼OðgpµÄ¢Ü·Bµ©µA È½Ì         
# IuWFNgt@CâÃICuÌ¼OÉ "-static" ðg¤        
# KvÍ èÜ¹ñB                                                   
                                                                       
gcc -Wall -g -c -o libhello-static.o libhello.c                        
                                                                       
# ÃICuðì¬µÜ·B                                         
                                                                       
ar rcs libhello-static.a libhello-static.o                             
                                                                       
# ±±ÅAlibhello-static.a ðg¤½ßÉ»êðÇ±©¼ÌêÖ         
# PÉRs[·é±ÆàÅ«Ü·BfªÚIÈÌÅACuÍ         
# JgfBNgàÉÆÇßÄ¨«Ü·B                           
                                                                       
# demo_use vOðRpCµÜ·B                              
                                                                       
gcc -Wall -g -c demo_use.c -o demo_use.o                               
                                                                       
# demo_use vOðì¬µÜ·B-L. ÉæèAvOì¬É      
# "." ªõ³êé±ÆÉÈèÜ·B±ÌR}hÍAlibhello-static.a    
# àÌÖW·éIuWFNgð demo_use_static ÉgÝÞÆ¢¤±Æ      
# ÉÓµÄ¾³¢B                                                 
                                                                       
gcc -g -o demo_use_static demo_use.o -L. -lhello-static                
                                                                       
# vOðÀsµÜ·B                                             
                                                                       
./demo_use_static                                                      

ªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªª

6.5. t@C script_shared

#!/bin/sh                                                               
# ¤LCuÌÀá                                                  
                                                                        
# ¤LCuÌIuWFNgt@C libhello.o ðì¬µÜ·B        
                                                                        
gcc -fPIC -Wall -g -c libhello.c                                        
                                                                        
# ¤LCuðì¬µÜ·B                                          
# libhello Í C CuÉË¶µÄ¢éÌÅAC CuÆ            
# N³¹é½ßÉ -lc IvVðg¢Ü·B                         
                                                                        
gcc -g -shared -Wl,-soname,libhello.so.0 \                              
    -o libhello.so.0.0 libhello.o -lc                                   
                                                                        
# ±±ÅAlibhello.so.0.0 ðÇ±©ÌfBNgA/usr/local/lib        
# ÈÇAÉPÉRs[Å«Ü·B                                          
                                                                        
# V{bNNðC³·é½ßAldconfig ðÄÑo·Kvª èÜ·B 
                                                                        
# soname ðÝèµÜ·BPÉA                                           
#                                                                       
#   ln -sf libhello.so.0.0 libhello.so.0                                
#                                                                       
# ðÀs·é¾¯Åàæ¢Å·ªAldconfig ÉâÁÄàç¢Üµå¤B       
                                                                        
/sbin/ldconfig -n .                                                     
                                                                        
# linker name ðÝèµÜ·B                                            
# æèôû³ê½Ýèð¨±È¤ÈçAùÉ linker name ª¶Ý·é©ð     
# mFµAàµ¶Ý·êÎA»êðcµÄ¨×«©Û©ð²×Ü·B        
                                                                        
ln -sf libhello.so.0 libhello.so                                        
                                                                        
# demo_use vOðRpCµÜ·B                               
                                                                        
gcc -Wall -g -c demo_use.c -o demo_use.o                                
                                                                        
# demo_use vOðì¬µÜ·B-L. ÉæèAvOì¬É       
# "." ªõ³êé±ÆÉÈèÜ·B±êÍAvOÀsÉ "."        
# ªõ³êé±ÆðÓ¡ 'µÈ¢' Æ¢¤±ÆÉÓµÄ¾³¢B        
                                                                        
gcc -g -o demo_use demo_use.o -L. -lhello                               
                                                                        
# vOðÀsµÜ·BLD_LIBRARY_PATH ðgÁÄAÇ±É¤L          
# Cuª¶Ý·é©ðvOÉ³¦éKvª é±ÆÉ          
# ÓµÄ¾³¢B                                                      
                                                                        
LD_LIBRARY_PATH="." ./demo_use                                          

ªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªª

6.6. t@C demo_dynamic.c

/* demo_dynamic.c -- ®I[fBOÆ "hello" [`gpÌÀá */  
                                                                       
                                                                       
/* ®IÉCuð[h·é[`pÉ dlfcn.h ªKv */          
#include                                                               
                                                                       
#include                                                               
                                                                       
/* "libhello.h" ðCN[h·éKvªÈ¢±ÆÉ                     
   ÓµÄ¾³¢Bµ©µÈªçAÖA·éàÌð                      
   wè·éKvÍ èÜ·Bdlsym() ©ç¾æ¤ÆµÄ                    
   ¢élðÛ·é^Cvðwè·éKvª èÜ·B*/                  
                                                                       
/* "simple_demo_function" ^CvÍAøðÆç¸A                     
   ½àlðÔ³È¢Öð¦µÄ¢Ü·B */                             
                                                                       
typedef void (*simple_demo_function)(void);                            
                                                                       
                                                                       
int main(void) {                                                       
 const char *error;                                                    
 void *module;                                                         
 simple_demo_function demo_function;                                   
                                                                       
 /* ®IÉ[h³êéCuð[h·é */                        
 module = dlopen("libhello.so", RTLD_LAZY);                            
 if (!module) {                                                        
   fprintf(stderr, "Couldn't open libhello.so: %s\n",                  
           dlerror());                                                 
   exit(1);                                                            
 }                                                                     
                                                                       
 /* V{ð¾é */                                                  
 dlerror();                                                            
 demo_function = dlsym(module, "hello");                               
 if ((error = dlerror())) {                                            
   fprintf(stderr, "Couldn't find hello: %s\n", error);                
   exit(1);                                                            
 }                                                                     
                                                                       
 /* DL CuàÌÖðÄÑo· */                                 
 (*demo_function)();                                                   
                                                                       
 /* SÄªI¹µ½ÌÅA¨ð«ê¢ÉÐt¯é */                      
 dlclose(module);                                                      
 return 0;                                                             
}                                                                      

ªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªªª

6.7. t@C script_dynamic

#!/bin/sh                                                              
# ®IÉ[h³êéCuÌÀá                                   
                                                                       
# libhello.so Æ»ÌÔªùÉì¬³êÄ¢éàÌÆµÜ·               
# (¤LCuÌáð©Ä¾³¢)B                                 
                                                                       
# demo_dynamic vOt@CðIuWFNgt@CÖ              
# RpCµÜ·B                                                   
                                                                       
gcc -Wall -g -c demo_dynamic.c                                         
                                                                       
# demo_use vOðì¬µÜ·B                                    
# ±ÌvOªgp·éBêÌÁÊÈCuÍAvO         
# N®ãÜÅ[h³êÈ¢ÌÅADL CuðÇ±ÉTµÉ¢          
# ¯Îæ¢©ð³¦éKvªÈ¢±ÆÉÚµÄ¾³¢Bµ©µÈ         
# ªçADL Cuð[h·éCuðÜßé½ßA-ldl          
# IvVÍ 'Kv' ÆÈèÜ·B                                     
                                                                       
gcc -g -o demo_dynamic demo_dynamic.o -ldl                             
                                                                       
# vOðÀsµÜ·BLD_LIBRARY_PATH ðg¢A®IÉ[h         
# ³êéCuðÇ±Å¾çêé©ð³¦éKvª èÜ·B           
                                                                       
LD_LIBRARY_PATH="." ./demo_dynamic                                     

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7. »Ì¼Ìîñ¹

ºLÌàÌÍACuÉÖµÄÁÉðÉ§ÂîñðÜñÅ¢Ü·B

 E Daniel Barlow Éæé ``The GCC HOWTO''. ÁÉ±Ì HOWTO ÍACu
    ì¬pÌIvVÆAÇÌæ¤ÉCuÉâ¢í¹ð·é©É
    Â¢Ä_¶Ä¢Ü·B±±ÅÍæèã°Ä¢È¢îñðµÁÄ¢Ü·ªA
    tÌ±Æà¾¦Ü·B±Ì HOWTO ÍA http://www.linuxdoc.org Ì
    Linux Documentation Project ©çüèÅ«Ü· (óF``The GCC
    HOWTO'' Ìú{êóÍ http://www.linux.or.jp/JF/JFdocs/
    GCC-HOWTO.html Å·)B
   
 E The Tool Interface Standards (TIS) ÏõïÉæé ``Executable and
    Linkable Format (ELF)'' (ÀÛÉÍ±êÍA¯ÏõïÉæé the
    Portable Formats Specification Version 1.1 àÌêÂÌÍÅ·). ±ê
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