Mac OS的链接器问题 [英] Issue with linker for Mac OS
问题描述
我最近在系统编程课程中开始将ada用于实验室，我可以说这真的很有趣.
I have recently started using ada for a lab in my systems programming class and I can say it is really interesting.
我在计算机实验室进行了大部分测试，我决定在 MacBook 中安装编译器及其链接工具.
I tried most of it at the computers labs for testing and I decided to install the compiler and its linking tools in a MacBook.
虽然安装已完成，但似乎没有问题，当我尝试打印经典的hello world程序时，我收到以下消息:
Altough the installation is done and there seems to be no problem, when I tried to print the classic hello world program I am getting this message:
gprbuild greet.adb
using project file /Users/xyderos/opt/GNAT/2020/share/gpr/_default.gpr
Bind
[gprbind] greet.bexch
[Ada] greet.ali
Link
[link] greet.adb
ld: library not found for -lSystem
collect2: error: ld returned 1 exit status
gprbuild: link of greet.adb failed
gprbuild: failed command was: /users/name/opt/gnat/2020/bin/gcc greet.o b__greet.o - L/Users/name/ada/ -L/Users/name/ada// -L/users/name/opt/gnat/2020/lib/gcc/x86_64-apple-darwin17.7.0/8.4.1/adalib/ /users/name/opt/gnat/2020/lib/gcc/x86_64-apple-darwin17.7.0/8.4.1/adalib/libgnat.a -Wl,-rpath,@executable_path/ -Wl,-rpath,@executable_path/..//opt/gnat/2020/lib/gcc/x86_64-apple-darwin17.7.0/8.4.1/adalib -o greet
我对lSystem库感到非常困惑.
I am getting really confused about the lSystem library.
该库似乎在Mac上不存在(也许我需要安装Xcode?).
It seems that the library doesn't exist on Mac(maybe I need to install Xcode?).
有人对这个问题有任何线索吗，或者有没有更好的方法可以通过brew安装它?
Does anyone have a clue about that issue or is there a probably better way to install it via brew?
非常感谢！
推荐答案
在我的MacOS 10.14上，以下代码对我有用，而不必下载Xcode庞大的Blob，而我既没有带宽也没有磁盘空间.我不知道这是否仍然可以在MacOS 10.15上使用(不打算升级).
On my MacOS 10.14, the following worked for me, without having to download the massive blob that is Xcode, which I had neither the bandwidth nor the diskspace for. I don't know if this still works on MacOS 10.15 (not planning to upgrade).
Most of this info was from a blog post by Simon Wright: https://forward-in-code.blogspot.com/2019/06/macos-software-development-kit-changes.html
- 您只需要Xcode命令行工具(不需要Xcode):
xcode-select --install - 现在解压缩包含的标题:
sudo installer -pkg/Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg -target/ - 然后告诉GNAT在哪里找到它们:
mv ce2109-specs/usr/local/opt/GNAT/2019/lib/gcc/x86_64-apple-darwin17.7.0/8.3.1/specs
ce2109-specs文件来自上面的博客文章.这为我完成了工作，GNAT现在可以在MacOS 10.14上链接工作二进制文件.
The ce2109-specs file is from the blog post above. This did the job for me and GNAT can now link working binaries on MacOS 10.14.
如果您使用的是10.15，但无法正常工作(因为没有更多的Xcode命令行工具，或者它们缺少标头包)，那么很遗憾，您必须按照GNAT自述文件安装Xcode.
If you're on 10.15 and it doesn't work (because there's no more Xcode command line tools or they're missing the headers package), you will unfortunately have to install Xcode as per the GNAT Readme.
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