This works by detecting output devices in build_input_stream() and
setting the AUDCLNT_STREAMFLAGS_LOOPBACK flag to enable loopback
recording.
closes#251
Currently CPAL only really uses `failure` for its `derive` capabilities
and the ability to easily generate implementations for `Display`. That
said there are a few issues with using the `failure` crate:
- `failure` does not provie a `std::error::Error` implementation without
first converting error types into `failure::Error`.
- It leaks significantly into the public API and expects downstream
users to also depend on `failure` and the non-std `Fail` trait for
their own error handling.
- Solved problems such as downcasting of causal errors which have since
been addressed in `std`.
- Provides application-friendly `Fail` trait and `failure::Error` type,
not particularly useful to libraries like CPAL.
The [`thiserror` crate](https://github.com/dtolnay/thiserror) is better
targeted towards libraries, does not leak into the public API while
providing easy generation of `Display`, `From` and `std::error::Error`
implementations including proper handling of the newish
`std::error::Error::source` method.
The hardcoded errno was replaced by a constant, and `snd_pcm_prepare` was replaced by `snd_pcm_recover` per best practice (the underlying implementation seems same for now, though).
This existed prior to the introduction of the `Host` API, but was lost
in translation. This re-adds the bounds so that downstream code does not
suddenly break due to a lacking `Hash` implementation in the next
CPAL version.
Most of this is an attempt at improving readability and modularity of
the asio-sys crate while attempting to review it for correctness. Still
unsure why glitching is occasionally occuring on output, but recorded
input sounds perfectly clean.