标题：gcc的参数顺序对链接的影响
出处：Felix021
时间：Thu, 02 Dec 2010 13:56:39 +0000
作者：felix021
地址：https://www.felix021.com/blog/read.php?1961

内容：
前一阵发现"gcc -static -lm a.c"总是会出现编译错误，后来不得已改成"gcc -static -lm a.c /usr/lib/libm.a"，才通过，也算是歪打正着。最近int ijk同学在使用我的woj-land，给我反馈了这个BUG，mark一下，并查到了原始文档，详情如下：

zz from http://gcc.gnu.org/onlinedocs/gcc/Link-Options.html

3.13 Options for Linking

......

-llibrary
-l library

Search the library named library when linking. (The second alternative with the library as a separate argument is only for POSIX compliance and is not recommended.)
It makes a difference where in the command you write this option; the linker searches and processes libraries and object files in the order they are specified. Thus, `foo.o -lz bar.o' searches library `z' after file foo.o but before bar.o. If bar.o refers to functions in `z', those functions may not be loaded.

The linker searches a standard list of directories for the library, which is actually a file named liblibrary.a. The linker then uses this file as if it had been specified precisely by name.

The directories searched include several standard system directories plus any that you specify with -L.

Normally the files found this way are library files—archive files whose members are object files. The linker handles an archive file by scanning through it for members which define symbols that have so far been referenced but not defined. But if the file that is found is an ordinary object file, it is linked in the usual fashion. The only difference between using an -l option and specifying a file name is that -l surrounds library with `lib' and `.a' and searches several directories. 


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