最近在做一个项目的客户端的SDK,实现为一个动态链接库,其依赖于其他的若干个动态库文件。那么在利用SDK开发应用程序的时候,编译的时候除了链接SDK库本身,还得链接SDK库所依赖的库,这样编译命令里面得一一的添加这些库。
比如,SDK库的名称为liba.so, 其依赖于libb.so和libc.so,那么在编译应用程序的时候使用以下命令:
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gcc -o test test.c -I. -L. -la -lb -lc
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但是如果将SDK库即liba.so交给其他的开发人员,其他的开发人员可不想编译的时候,显示的链接liba.so所依赖的库。他们更愿意编译的时候,只显示地链接liba.so。
那么该怎么做呢?利用rpath这个链接选项!
首先来man ld,查找链接选项rpath的含义:
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-rpath dir
Add a directory to the runtime library search path. This is used when linking an ELF executable with
shared objects. All -rpath arguments are concatenated and passed to the runtime linker, which uses
them to locate shared objects at runtime. The -rpath option is also used when locating shared objects
which are needed by shared objects explicitly included in the link; see the description of the
-rpath-link option. If -rpath is not used when linking an ELF executable, the contents of the environ-
ment variable "LD_RUN_PATH" will be used if it is defined.
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简单翻译下, rpath链接选项主要有两个功能:
(1)程序运行时,优先到rpath指定的目录去寻找依赖库
(2)程序链接时,在指定的目录中,隐式的链接那些动态库所需要的链接库。
往往我们都熟知第一个功能,忽略第二个功能。而第二个功能正是现在所需要的。
我们将liba.so,libb.so 和 libc.so拷贝的同一个目录中,然后利用rpath链接应用程序,这样编译便不需要显示的去链接liba.so所依赖的库了。
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gcc -o test test.c -I. -L. -la -Wl,-rpath=.
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链接选项rpath,容易被忽略的一个功能,布布扣,bubuko.com
原文:http://blog.csdn.net/cjf_iceking/article/details/25219675