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... g++ ../source/authorisecfg.o ../source/bmcinst.o ../source/config.o ../source/lgsinst.o ../source/logicsrv.o ../source/logicsrvinst.o ../source/logicsrvmodulelistcfg.o ../source/main.o ../source/moduleinst.o ../source/print.o ../source/routingkeycfg.o ../source/sautils.o ../source/structself.o ../source/../../../common/source/bossutils.o ../source/../../../common/source/bossversion.o -o sa -m32 -L../../../../10-common/lib/release/linux -lrt -lwatchdogclient -lfiletransfer -losp -lkprop -ljsonconvert -ljsoncpp -ldeploycfg -lnosectionini -lrabbitmq_r -lmqwrapper -lreadwritelock -lcaptureexception -lnetconfig /usr/bin/ld: warning: libevent_core.so, needed by ../../../../10-common/lib/release/linux/librabbitmq_r.so, not found (try using -rpath or -rpath-link) /usr/bin/ld: warning: libevent_pthreads.so, needed by ../../../../10-common/lib/release/linux/librabbitmq_r.so, not found (try using -rpath or -rpath-link) ../../../../10-common/lib/release/linux/librabbitmq_r.so: undefined reference to `event_base_free‘ ../../../../10-common/lib/release/linux/librabbitmq_r.so: undefined reference to `evthread_use_pthreads‘ ../../../../10-common/lib/release/linux/librabbitmq_r.so: undefined reference to `event_assign‘ ../../../../10-common/lib/release/linux/librabbitmq_r.so: undefined reference to `event_base_dispatch‘ ../../../../10-common/lib/release/linux/librabbitmq_r.so: undefined reference to `event_base_loopbreak‘ ../../../../10-common/lib/release/linux/librabbitmq_r.so: undefined reference to `event_del‘ ../../../../10-common/lib/release/linux/librabbitmq_r.so: undefined reference to `event_add‘ ../../../../10-common/lib/release/linux/librabbitmq_r.so: undefined reference to `event_base_new‘ collect2: ld returned 1 exit status make: *** [sa] Error 1由错误信息可以看出，未找到的符号均属于 libevent_core.so 和 libevent_pthreads.so 内部。但这两个库确实存在于 -L../../../../10-common/lib/release/linux 路径下，但为什么链接器仍旧无法找到对应的库和符号呢？
[root@Betty include_test]# ll 总用量 20 -rw-r--r-- 1 root root 149 9月 14 16:19 main.c -rw-r--r-- 1 root root 123 9月 14 16:40 say_hello.c -rw-r--r-- 1 root root 20 9月 14 15:58 say_hello.h -rw-r--r-- 1 root root 416 9月 14 16:39 time_print.c -rw-r--r-- 1 root root 69 9月 14 15:00 time_print.h [root@Betty include_test]#
// g++ -o say_hello.so -fpic -shared say_hello.c
#include <stdio.h>
void say_hello()
{
printf( "Hello World!\n" );
}
【say_hello.h】 void say_hello();【time_print.c】
// g++ -o time_print.so -fpic -shared -I. -L. time_print.c say_hello.so
#include <time_print.h>
#include <stdio.h>
#include <say_hello.h>
int time_print( time_t tmp )
{
int off = 0;
time_t t;
char buf[64] = {0};
t = time( NULL );
off = strftime( buf, sizeof(buf), "%d %b %H:%M:%S", localtime( &t ) );
fprintf( stderr, "current timestamp = %s\n", buf );
say_hello();
return 0;
}
【time_print.h】 #include <time.h> int time_print( time_t t );【main.c 】
// g++ -o main main.c time_print.so -I. -Wl,-rpath-link,.
#include <time_print.h>
int main()
{
time_t t;
time_print( t );
return 0;
}
[root@Betty include_test]# g++ -o say_hello.so -fpic -shared say_hello.c [root@Betty include_test]# ll 总用量 28 -rw-r--r-- 1 root root 149 9月 14 16:19 main.c -rw-r--r-- 1 root root 123 9月 14 16:40 say_hello.c -rw-r--r-- 1 root root 20 9月 14 15:58 say_hello.h -rwxr-xr-x 1 root root 6286 9月 15 19:31 say_hello.so -rw-r--r-- 1 root root 416 9月 14 16:39 time_print.c -rw-r--r-- 1 root root 69 9月 14 15:00 time_print.h [root@Betty include_test]# [root@Betty include_test]# g++ -o time_print.so -fpic -shared -I. -L. time_print.c say_hello.so [root@Betty include_test]# ll 总用量 36 -rw-r--r-- 1 root root 149 9月 14 16:19 main.c -rw-r--r-- 1 root root 123 9月 14 16:40 say_hello.c -rw-r--r-- 1 root root 20 9月 14 15:58 say_hello.h -rwxr-xr-x 1 root root 6286 9月 15 19:31 say_hello.so -rw-r--r-- 1 root root 416 9月 14 16:39 time_print.c -rw-r--r-- 1 root root 69 9月 14 15:00 time_print.h -rwxr-xr-x 1 root root 7117 9月 15 19:31 time_print.so [root@Betty include_test]#若不指定 -rpath-link 选项，则链接失败
[root@Betty include_test]# g++ -o main main.c time_print.so -I. -L. /usr/bin/ld: warning: say_hello.so, needed by time_print.so, not found (try using -rpath or -rpath-link) time_print.so: undefined reference to `say_hello()‘ collect2: ld 返回 1 [root@Betty include_test]#若指定 -rpath-link 选项，则可以成功链接
[root@Betty include_test]# g++ -o main main.c time_print.so -I. -L. -Wl,-rpath-link,. [root@Betty include_test]# ll 总用量 44 -rwxr-xr-x 1 root root 6999 9月 15 19:37 main -rw-r--r-- 1 root root 149 9月 14 16:19 main.c -rw-r--r-- 1 root root 123 9月 14 16:40 say_hello.c -rw-r--r-- 1 root root 20 9月 14 15:58 say_hello.h -rwxr-xr-x 1 root root 6286 9月 15 19:31 say_hello.so -rw-r--r-- 1 root root 416 9月 14 16:39 time_print.c -rw-r--r-- 1 root root 69 9月 14 15:00 time_print.h -rwxr-xr-x 1 root root 7117 9月 15 19:31 time_print.so [root@Betty include_test]#查看一下共享库依赖关系
[root@Betty include_test]# ldd say_hello.so
linux-vdso.so.1 => (0x00007fffb53ff000)
libstdc++.so.6 => /usr/lib64/libstdc++.so.6 (0x00007f56915d4000)
libm.so.6 => /lib64/libm.so.6 (0x00007f5691350000)
libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007f5691139000)
libc.so.6 => /lib64/libc.so.6 (0x00007f5690da5000)
/lib64/ld-linux-x86-64.so.2 (0x000000388c400000)
[root@Betty include_test]#
[root@Betty include_test]# ldd time_print.so
linux-vdso.so.1 => (0x00007fff50cfa000)
say_hello.so => not found
libstdc++.so.6 => /usr/lib64/libstdc++.so.6 (0x00007ff0f7829000)
libm.so.6 => /lib64/libm.so.6 (0x00007ff0f75a5000)
libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007ff0f738f000)
libc.so.6 => /lib64/libc.so.6 (0x00007ff0f6ffa000)
/lib64/ld-linux-x86-64.so.2 (0x000000388c400000)
[root@Betty include_test]#
[root@Betty include_test]# ldd main
linux-vdso.so.1 => (0x00007fffc55ff000)
time_print.so => not found
libstdc++.so.6 => /usr/lib64/libstdc++.so.6 (0x0000003899800000)
libm.so.6 => /lib64/libm.so.6 (0x000000388dc00000)
libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x0000003898000000)
libc.so.6 => /lib64/libc.so.6 (0x000000388c800000)
/lib64/ld-linux-x86-64.so.2 (0x000000388c400000)
[root@Betty include_test]#
执行程序 [root@Betty include_test]# ./main ./main: error while loading shared libraries: time_print.so: cannot open shared object file: No such file or directory [root@Betty include_test]# [root@Betty include_test]# LD_LIBRARY_PATH=. ./main current timestamp = 15 Sep 19:41:00 Hello World! [root@Betty include_test]#最后给出一个 rpath 递归问题的讨论： 《Resursive linking with rpath》
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原文地址：http://my.oschina.net/moooofly/blog/506466
