g ++：如何指定库路径的首选项？ [英] g++: how to specify preference of library path?

问题描述

我正在使用 g ++ 和 ld 编译一个c ++程序。我有一个 .so 库我想在链接过程中使用。但是，在 / usr / local / lib 中存在同名的库，而 ld 我直接指定的。

I'm compiling a c++ program using g++ and ld. I have a .so library I want to be used during linking. However, a library of the same name exists in /usr/local/lib, and ld is choosing that library over the one I'm directly specifying. How can I fix this?

对于下面的示例，我的库文件为 /my/dir/libfoo.so.0 。我尝试过的东西不起作用：

For the examples below, my library file is /my/dir/libfoo.so.0. Things I've tried that don't work:

• 我的g ++命令是 g ++ -g -Wall -o my_binary -L / my / dir -lfoo bar.cpp


• 添加 / my / dir $ PATH en`变量


• 添加 /my/dir/libfoo.so的开头或结尾。 0 作为g ++的参数

• my g++ command is g++ -g -Wall -o my_binary -L/my/dir -lfoo bar.cpp
• adding /my/dir to the beginning or end of my $PATH en` variable
• adding /my/dir/libfoo.so.0 as an argument to g++

推荐答案

LD_LIBRARY_PATH （在Mac上有稍微不同的名称）的路径

Add the path to where your new library is to LD_LIBRARY_PATH (it has slightly different name on Mac ...)

您的解决方案应该使用 -L / my / dir -lfoo 选项，在运行时使用LD_LIBRARY_PATH指向库的位置。

Your solution should work with using the -L/my/dir -lfoo options, at runtime use LD_LIBRARY_PATH to point to the location of your library.

OR

使用rpath选项通过gcc到链接器 - 运行时库搜索路径，将使用
（gcc选项）：

Use the rpath option via gcc to linker - runtime library search path, will be used instead of looking in standard dir (gcc option):

-Wl,-rpath,$(DEFAULT_LIB_INSTALL_PATH)

这对于临时解决方案很有用。链接器在查找标准目录之前首先搜索库的LD_LIBRARY_PATH。

This is good for a temporary solution. Linker first searches the LD_LIBRARY_PATH for libraries before looking into standard directories.

如果不想永久更新LD_LIBRARY_PATH，可以在命令行中执行： / p>

If you don't want to permanently update LD_LIBRARY_PATH you can do it on the fly on command line:

LD_LIBRARY_PATH=/some/custom/dir ./fooo

您可以检查链接器知道使用哪些库（示例）：

You can check what libraries linker knows about using (example):

/sbin/ldconfig -p | grep libpthread
        libpthread.so.0 (libc6, OS ABI: Linux 2.6.4) => /lib/libpthread.so.0

您可以检查您的应用程序正在使用哪个库： p>

And you can check which library your application is using:

ldd foo
        linux-gate.so.1 =>  (0xffffe000)
        libpthread.so.0 => /lib/libpthread.so.0 (0xb7f9e000)
        libxml2.so.2 => /usr/lib/libxml2.so.2 (0xb7e6e000)
        librt.so.1 => /lib/librt.so.1 (0xb7e65000)
        libm.so.6 => /lib/libm.so.6 (0xb7d5b000)
        libc.so.6 => /lib/libc.so.6 (0xb7c2e000)
        /lib/ld-linux.so.2 (0xb7fc7000)
        libdl.so.2 => /lib/libdl.so.2 (0xb7c2a000)
        libz.so.1 => /lib/libz.so.1 (0xb7c18000)

这篇关于g ++：如何指定库路径的首选项？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！