使用Preferred-dynamic时无法执行Hello World项目 [英] Unable to execute a hello world project when using prefer-dynamic

问题描述

我在一个非常简单的项目Hello World中使用Rust的编译选项：

I'm playing with Rust's compilation options on an extremely simple project, hello world:

fn main() {
    println!("Hello, world!");
}

我正在编译此行，prefer-dynamic是唯一值得注意的选择：

I'm compiling with this line, prefer-dynamic is the only notable option:

rustc main.rs -o ./build/rci -C prefer-dynamic

工作正常，直到我进行了一些更改，然后才进行了更改。现在，如果我尝试完全像上面那样编译代码，我将得到以下输出：

It was working fine until I made some changes and then it didn't. Now if I try to compile the code exactly as above I get this output:

./build/rci: error while loading shared libraries: libstd-2ddb28df747fcb8c.so: cannot open shared object file: No such file or directory

ldd的输出是：

linux-vdso.so.1 =>  (0x00007ffd321a4000)
libstd-2ddb28df747fcb8c.so => not found
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f52eaef3000)
/lib64/ld-linux-x86-64.so.2 (0x000055f0f6251000)

这是在带有Rust 1.15.1的Ubuntu 17.04上。

This is on Ubuntu 17.04 with Rust 1.15.1.

推荐答案

您应该查看术语；编程时，单词表示特定的事物。如您所见，调用Rust编译器（又名 rustc ）没有任何错误，就可以很好地编译代码。

You should review your terminology; words mean specific things when programming. You are able to compile your code just fine, as shown by the fact that invoking the Rust compiler (a.k.a. rustc) doesn't have any errors.

您的问题是在执行程序时发生的。这些是非常不同的概念，它将使您很好地理解它们之间的区别。

Your problem occurs when executing the program. These are very different concepts and it will serve you well to understand the difference.

问题是您...正在使用动态链接，就像您ve要求。这不是不是 Rust问题，只是一般的编程问题。我确定有很多SO问题，例如加载共享库时发生Linux错误：无法打开共享对象文件：没有此类文件或目录或该错误消息还有500个其他问题，可以为您提供更多信息。

The "problem" is that you... are using dynamic linking, just like you've asked for. This is not a Rust issue, just a general programming issue. I'm sure there are numerous SO questions, such as Linux error while loading shared libraries: cannot open shared object file: No such file or directory or one of the 500 other questions with that error message that can provide you with more information.

您正在动态链接到Rust标准库，但是您的系统不知道该库，因为它没有安装在系统知道的位置。您很可能是通过rustup安装的，因此该库位于主目录中。例如，我的位于 /home/ubuntu/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/libstd-f4594d3e53dcb114.so 。

You are dynamically linking against the Rust standard library, but your system doesn't know about that library because it's not installed in a location your system knows about. Most likely, you've installed via rustup, so the library is in your home directory. For example, mine is in /home/ubuntu/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/libstd-f4594d3e53dcb114.so.

您会找到许多可能的解决方案。最简单的示例是使用 LD_LIBRARY_PATH 变量：

You will find many possible solutions. The easiest to demonstrate is using the LD_LIBRARY_PATH variable:

$ ./example
./example: error while loading shared libraries: libstd-f4594d3e53dcb114.so: cannot open shared object file: No such file or directory
$ LD_LIBRARY_PATH=/home/ubuntu/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/ ./example
Hello, world!

您也可以查看将Rust应用程序与不在运行时链接程序搜索路径中的动态库链接

发现这一点，您可以使Rust 打印出它使用的链接器调用：

To help discover this, you can make Rust print out the linker invocation it uses:

$ rustc +nightly -Cprefer-dynamic -Z print-link-args hello.rs
"cc" "-m64" "-L" "/Users/shep/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib" "hello.hello0.rcgu.o" "hello.hello1.rcgu.o" "hello.hello2.rcgu.o" "hello.hello3.rcgu.o" "hello.hello4.rcgu.o" "hello.hello5.rcgu.o" "-o" "hello" "hello.crate.allocator.rcgu.o" "-Wl,-dead_strip" "-nodefaultlibs" "-L" "/Users/shep/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib" "-L" "/Users/shep/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib" "-l" "std-834fbefe8dbe98b5" "/Users/shep/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib/libcompiler_builtins-b4312e2f1496a4e4.rlib" "-l" "System" "-l" "resolv" "-l" "pthread" "-l" "c" "-l" "m"

您可以看到 -L /Users/shep/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib 已添加到链接器路径，然后-l std-834fbefe8dbe98b5 链接标准库。

You can see that "-L" "/Users/shep/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/x86_64-apple-darwin/lib" was added to the linker path and then "-l" "std-834fbefe8dbe98b5" links the standard library.

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