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gcc 的 -ldl 参数是什么意思?

  •  
  •   rrfeng · 2013-04-27 17:22:15 +08:00 · 11920 次点击
    这是一个创建于 4227 天前的主题,其中的信息可能已经有所发展或是发生改变。
    情景:
    编译安装 keepalived,需要 openssl-devel 的库

    但是 openssl 也是编译安装的,安装目录是 /usr/local/openssl

    keepalived configure 的时候,无论是
    --libdir=/usr/local/openssl
    还是
    LDFLAGS="$LDFLAGS -L/usr/local/openssl" ;
    或者指定 /usr/local/openssl/lib /usr/local/openssl/include 等目录

    均提示 OpenSSL 库找不到。



    最终在
    LDFLAGS="-ldl" ./configure
    的时候编译成功了,成功的自动找到了 openssl 中相关文件
    2 条回复    1970-01-01 08:00:00 +08:00
    wwwjfy
        1
    wwwjfy  
       2013-04-27 17:53:30 +08:00   ❤️ 1
    -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.


    -L 只是加入搜索库的路径,-l指定要链接的库
    -ldl, dl就是库的名字
    seupengdi
        2
    seupengdi  
       2013-04-27 23:55:12 +08:00
    就是libdl.so吧 某种有用的动态库
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