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# `export-executable-symbols`
The tracking issue for this feature is: [#84161](https://github.com/rust-lang/rust/issues/84161).
------------------------
The `-Zexport-executable-symbols` compiler flag makes `rustc` export symbols from executables. The resulting binary is runnable, but can also be used as a dynamic library. This is useful for interoperating with programs written in other languages, in particular languages with a runtime like Java or Lua.
For example on windows:
```rust
#[no_mangle]
fn my_function() -> usize {
return 42;
}
fn main() {
println!("Hello, world!");
}
```
A standard `cargo build` will produce a `.exe` without an export directory. When the `export-executable-symbols` flag is added
```Bash
export RUSTFLAGS="-Zexport-executable-symbols"
cargo build
```
the binary has an export directory with the functions:
```plain
The Export Tables (interpreted .edata section contents)
...
[Ordinal/Name Pointer] Table
[ 0] my_function
[ 1] main
```
(the output of `objdump -x` on the binary)
Please note that the `#[no_mangle]` attribute is required. Without it, the symbol is not exported.
The equivalent of this flag in C and C++ compilers is the `__declspec(dllexport)` annotation or the `-rdynamic` linker flag.
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