wasm-pack support

[glauserr]

The crate does not support to be compiled with wasm32-unknown-unknown. It there any will to add support for it in the close future?

$ wasm-pack build 

error[E0433]: failed to resolve: use of undeclared type or module `sys`
    --> /home/regl/.cargo/registry/src/github.com-1ecc6299db9ec823/errno-0.2.4/src/lib.rs:35:9
     |
  35 |         sys::with_description(*self, |desc| {
     |         ^^^ use of undeclared type or module `sys`
  
  error[E0433]: failed to resolve: use of undeclared type or module `sys`
    --> /home/regl/.cargo/registry/src/github.com-1ecc6299db9ec823/errno-0.2.4/src/lib.rs:46:9
     |
  46 |         sys::with_description(*self, |desc| match desc {
     |         ^^^ use of undeclared type or module `sys`
  
  error[E0433]: failed to resolve: use of undeclared type or module `sys`
    --> /home/regl/.cargo/registry/src/github.com-1ecc6299db9ec823/errno-0.2.4/src/lib.rs:50:25
     |
  50 |                 self.0, sys::STRERROR_NAME, fm_err.0),
     |                         ^^^ use of undeclared type or module `sys`
  
  error[E0433]: failed to resolve: use of undeclared type or module `sys`
    --> /home/regl/.cargo/registry/src/github.com-1ecc6299db9ec823/errno-0.2.4/src/lib.rs:69:5
     |
  69 |     sys::errno()
     |     ^^^ use of undeclared type or module `sys`
  
  error[E0433]: failed to resolve: use of undeclared type or module `sys`
    --> /home/regl/.cargo/registry/src/github.com-1ecc6299db9ec823/errno-0.2.4/src/lib.rs:74:5
     |
  74 |     sys::set_errno(err)
     |     ^^^ use of undeclared type or module `sys`
  

[lambda-fairy]

What would you like the library to do in this case?

If you want to match what std does -- have a placeholder that returns 0 -- then that's okay with me. My only concern is that it might be confusing, especially if std adds a real errno implementation in the future.

[lambda-fairy]

Also, what's your use case for this? Most of the packages that depend on errno don't make sense on the web anyway.

[Zaechus]

I'm having the same issue when compiling to wasm32-wasi. The build fails with the same error message for both stable and nightly channels.

[lambda-fairy]

WASI support sounds reasonable to me. I'll be happy to review a PR that adds it.

[lambda-fairy]

We support WASI now, so I believe this can be closed.

[Itanq]

We support WASI now, so I believe this can be closed.

Hi @lambda-fairy , Could you please tell me in which version the support for wasm was added?
I use the latest version(v0.2.5), the problem still here. as following:

cargo build --target=wasm32-unknown-unknown
---------------
error[E0433]: failed to resolve: use of undeclared type or module `sys`
  --> D:\Environments\.cargo\registry\src\mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd\errno-0.2.5\src\lib.rs:40:9
   |
40 |         sys::with_description(*self, |desc| {
   |         ^^^ use of undeclared type or module `sys`

error[E0433]: failed to resolve: use of undeclared type or module `sys`
  --> D:\Environments\.cargo\registry\src\mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd\errno-0.2.5\src\lib.rs:51:9
   |
51 |         sys::with_description(*self, |desc| match desc {
   |         ^^^ use of undeclared type or module `sys`

error[E0433]: failed to resolve: use of undeclared type or module `sys`
  --> D:\Environments\.cargo\registry\src\mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd\errno-0.2.5\src\lib.rs:55:25
   |
55 |                 self.0, sys::STRERROR_NAME, fm_err.0),
   |                         ^^^ use of undeclared type or module `sys`

error[E0433]: failed to resolve: use of undeclared type or module `sys`
  --> D:\Environments\.cargo\registry\src\mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd\errno-0.2.5\src\lib.rs:74:5
   |
74 |     sys::errno()
   |     ^^^ use of undeclared type or module `sys`

error[E0433]: failed to resolve: use of undeclared type or module `sys`
  --> D:\Environments\.cargo\registry\src\mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd\errno-0.2.5\src\lib.rs:79:5
   |
79 |     sys::set_errno(err)
   |     ^^^ use of undeclared type or module `sys`

error[E0277]: the size for values of type `str` cannot be known at compilation time
  --> D:\Environments\.cargo\registry\src\mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd\errno-0.2.5\src\lib.rs:52:16
   |
52 |             Ok(desc) => fmt.write_str(&desc),
   |                ^^^^ doesn't have a size known at compile-time
   |
   = help: the trait `std::marker::Sized` is not implemented for `str`
   = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
   = note: all local variables must have a statically known size
   = help: unsized locals are gated as an unstable feature

error[E0277]: the size for values of type `str` cannot be known at compilation time
  --> D:\Environments\.cargo\registry\src\mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd\errno-0.2.5\src\lib.rs:52:13
   |
52 |             Ok(desc) => fmt.write_str(&desc),
   |             ^^^^^^^^ doesn't have a size known at compile-time
   |
   = help: the trait `std::marker::Sized` is not implemented for `str`
   = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
   = note: required by `std::prelude::v1::Ok`

error[E0277]: the size for values of type `str` cannot be known at compilation time
  --> D:\Environments\.cargo\registry\src\mirrors.tuna.tsinghua.edu.cn-df7c3c540f42cdbd\errno-0.2.5\src\lib.rs:53:13
   |
53 |             Err(fm_err) => write!(
   |             ^^^^^^^^^^^ doesn't have a size known at compile-time
   |
   = help: the trait `std::marker::Sized` is not implemented for `str`
   = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
   = note: required by `std::prelude::v1::Err`

error: aborting due to 8 previous errors

Some errors have detailed explanations: E0277, E0433.
For more information about an error, try `rustc --explain E0277`.
error: could not compile `errno`.

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: build failed

[lambda-fairy]

@Itanq try rust nightly with the wasm32-wasi target, as mentioned in CI:

https://github.com/lambda-fairy/rust-errno/blob/master/.travis.yml

wasm32-unknown-unknown is bare WASM with no WASI, so I don't think it should work there.

[Itanq]

@Itanq try rust nightly with the wasm32-wasi target, as mentioned in CI:

https://github.com/lambda-fairy/rust-errno/blob/master/.travis.yml

wasm32-unknown-unknown is bare WASM with no WASI, so I don't think it should work there.

got it, it work, thank you very much!