ldd 函式庫工具

1. Linux 放置函式庫之目錄：

   [dywang@dyw219 make1]$ ll -d /lib{,64} /usr/lib{,64}
   dr-xr-xr-x.  12 root root  4096 Nov 29 18:10 /lib
   dr-xr-xr-x.  10 root root 12288 Sep 29  2018 /lib64
   dr-xr-xr-x.  33 root root  4096 Nov 29 18:10 /usr/lib
   dr-xr-xr-x. 146 root root 77824 Feb 14 03:33 /usr/lib64
   

2. ldd 輔助說明

   [dywang@dyw219 make1]$ ldd --help
   Usage: ldd [OPTION]... FILE...
         --help              print this help and exit
         --version           print version information and exit
     -d, --data-relocs       process data relocations
     -r, --function-relocs   process data and function relocations
     -u, --unused            print unused direct dependencies
     -v, --verbose           print all information
   
   For bug reporting instructions, please see:
   <http://www.gnu.org/software/libc/bugs.html>.
   

3. 找出執行檔 main 使用的那些動態函式庫？

   [dywang@dyw219 make1]$ ldd main
   	linux-vdso.so.1 =>  (0x00007ffe741f9000)
   	libc.so.6 => /lib64/libc.so.6 (0x000000394aa00000)
   	/lib64/ld-linux-x86-64.so.2 (0x000055836ce6b000)
   

4. 再找出函式 /lib64/libc.so.6 的相關其他函式庫。

   [dywang@dyw219 make1]$ ldd /lib64/libc.so.6 
   	/lib64/ld-linux-x86-64.so.2 (0x0000558d8c22f000)
   	linux-vdso.so.1 =>  (0x00007ffd3d158000)