对“dlsym"和“dlopen"的未定义引用 [英] Undefined reference to 'dlsym' and 'dlopen'
问题描述
我正在使用 arm-linux-gnueabi-g++ 4.7.3 版进行编译.
I am compiling using arm-linux-gnueabi-g++ version 4.7.3.
我在以下位置安装了 arm-linux-gnueabi 库:
I have the arm-linux-gnueabi libraries installed at location:
/usr/arm-linux-gnueabi/lib,它包含libdl.a、libdl.so、libdl.so.2、和 libdl-2.19.so.
/usr/arm-linux-gnueabi/lib, it contains libdl.a, libdl.so, libdl.so.2, and libdl-2.19.so.
libdl.so 链接到 libdl.so.2,后者链接到 libdl-2.19.so.
libdl.so links to libdl.so.2 which links to libdl-2.19.so.
我正在尝试链接 dl 库(请参阅下面的命令字符串),但我总是收到未定义的引用错误.
I am trying to link against the dl library (see command string below), but I always get the undefined reference errors.
arm-linux-gnueabi-g++ -I. -I../ -I../Comms/Linux -Wall -DLINUX -fpic -o ../../work/MyProgram main.o
-L../../work -L/usr/arm-linux-gnueabi/lib -lComms -lConsole -lUtilities -ldl
../../work/libUtilities.so: undefined reference to `dlsym'
../../work/libUtilities.so: undefined reference to `dlopen'
collect2: error: ld returned 1 exit status
如果我使用以下命令使用 g++ 4.8.2 进行编译,那么我的程序可以正常编译、链接和执行.
If I compile using g++ 4.8.2 using the following commend then my program compiles, links, and executes fine.
g++ -I. -I../ -I../Comms/Linux -Wall -DLINUX -fpic -o ../../work/MyProgram main.o
-L../../work -lComms -lConsole -lUtilities -ldl
显然找不到libdl.so库;我认为通过使用 -L
标志添加到适当库位置的路径可以解决问题,但它没有.
Obviously it can't find the libdl.so library; I thought that by adding the path to the location of the appropriate library by using the -L
flag would fix the problem, but it didn't.
我在 ARM 编译器命令中遗漏了什么?
What am I missing with the ARM compiler command?
推荐答案
好吧,我找到了答案,我需要 -Wl,--no-as-needed
标志在 - 之前ldl
.在我问这个问题之前,我遇到过这个标志,但显然打错了它,因为它对我不起作用.
Well, I found the answer, I needed -Wl,--no-as-needed
flag before the -ldl
. I had run across this flag before I asked the question, but apparently mistyped it because it hadn't worked for me.
我不明白为什么需要标志,但代码现在确实完成了链接.
I don't understand why the flag is needed, but the code does finish linking now.
SO 用户 here 说这与最近的 (2013 年用户的帖子)链接到 --as-needed 的 gcc 版本.
A SO user here says that it has to do with recent (2013 as of the user's post) versions of gcc linking to --as-needed.
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