Unresolved imports `libc::c_void`, `libc::memcmp` for WASM

[k06a]

I just tried to use it for WASM:

ethereum-bigint = "0.2.9"

   Compiling ethereum-bigint v0.2.9
error[E0432]: unresolved imports `libc::c_void`, `libc::memcmp`
  --> /Users/k06a/.cargo/registry/src/github.com-1ecc6299db9ec823/ethereum-bigint-0.2.9/src/hash/mod.rs:25:36
   |
25 | #[cfg(feature = "std")] use libc::{c_void, memcmp};
   |                                    ^^^^^^  ^^^^^^ no `memcmp` in the root
   |                                    |
   |                                    no `c_void` in the root

error: aborting due to previous error

For more information about this error, try `rustc --explain E0432`.
error: Could not compile `ethereum-bigint`.
warning: build failed, waiting for other jobs to finish...
error: build failed

[gnzlbg]

Could you write down the command that you are using to compile ?

[JohnTitor]

AFAIK they should be available and this is stale in over a year so I'm going to close this. Feel free to comment with additional information, I'm happy to re-open then :)

[kylebarron]

These are still not available for wasm32-unknown-unknown. If you try to compile a project using libc to wasm32-unknown-unknown, you'll get these errors. E.g with https://github.com/georust/geos/tree/e1dc4ec6623a3d9ca45a4b531a0bacd5522b5b85, I get:

> cargo build --target wasm32-unknown-unknown
   Compiling geos-sys v2.0.4 (/Users/kbarron/github/rust/geos/sys)
   Compiling num v0.4.0
warning: dropping unsupported crate type `dylib` for target `wasm32-unknown-unknown`

error[E0432]: unresolved imports `libc::c_char`, `libc::c_double`, `libc::c_int`, `libc::c_uchar`, `libc::c_uint`, `libc::c_void`, `libc::size_t`
 --> sys/src/functions.rs:2:12
  |
2 | use libc::{c_char, c_double, c_int, c_uchar, c_uint, c_void, size_t};
  |            ^^^^^^  ^^^^^^^^  ^^^^^  ^^^^^^^  ^^^^^^  ^^^^^^  ^^^^^^ no `size_t` in the root
  |            |       |         |      |        |       |
  |            |       |         |      |        |       no `c_void` in the root
  |            |       |         |      |        no `c_uint` in the root
  |            |       |         |      no `c_uchar` in the root
  |            |       |         no `c_int` in the root
  |            |       no `c_double` in the root
  |            no `c_char` in the root

error[E0432]: unresolved imports `libc::c_char`, `libc::c_double`, `libc::c_void`
 --> sys/src/types.rs:1:12
  |
1 | use libc::{c_char, c_double, c_void};
  |            ^^^^^^  ^^^^^^^^  ^^^^^^ no `c_void` in the root
  |            |       |
  |            |       no `c_double` in the root
  |            no `c_char` in the root

For more information about this error, try `rustc --explain E0432`.
warning: `geos-sys` (lib) generated 1 warning
error: could not compile `geos-sys` due to 2 previous errors; 1 warning emitted

This looks like a duplicate of #858 essentially