This avoids relying on Android 5.0 / API level 21. The Linux kernel used
by Android supports the syscall (except in truly ancient Android
versions), but the Android libc did not expose a wrapper.
We leave IPPROTO_MAX as is for the time being. However, in recent
kernel releases IPPROTO_MAX is actually higher and reflects the
addition of IPPROTO_MPTCP.
These constant can be used to determine the maximum number of iovecs can
be passed to functions like readv/writev.
Linux like uses UIO_MAXIOV, while the BSD family uses IOV_MAX.
Linux defines a waitid type `P_PIDFD`, for use with process file
descriptors (`pidfd`). Add that constant.
In libc-test, add linux/wait.h to the Linux-specific and
Android-specific headers, to get the definition. Exclude it on Android
and musl for now, though, as the versions in CI don't have it yet.
On Linux, `sys/wait.h` defines a `W_STOPCODE` macro to construct a stop
code from the signal number of a stopping signal. Provide an equivalent
function.
Suggested-by: Ivan Tham <pickfire@riseup.net>
sock_extended_err is a struct returned as a control message when the sockopt
IP_RECVERR is set, when recvmsg has the MSG_ERRQUEUE flag set. IP_RECVERR and
MSG_ERRQUEUE are constants both already defined here.
Add support for making functions `const`
PR https://github.com/rust-lang/rust/pull/64906 adds the ability to write `const extern fn` and `const unsafe extern fn`, which will allow manys functions in `libc` to become `const`.
This is particuarly useful for functions which correspond to C macros (e.g. `CMSG_SPACE`). In C, these macros are constant expressions, allowing them to be used when declaring arrays. However, since the corresponding `libc` functions are not `const`, writing equivalent Rust code is impossible. Users must either perform an unecessary heap allocation, or pull in `bindgen` to evaluate the macro for specific values (e.g. `CMSG_SPACE(1)`).
However, the syntax `const extern fn` is not currently parsed by rust. To allow libc to use this without breaking backwards compatibility (i.e. bumping the minimum Rust version), I've taken the following approach:
1. A new off-by-default feature `extern-const-fn` is added to `libc`.
2. The internal `f!` macro has two versions, selected at compile-time by a `cfg_if`. When `extern-const-fn` is enabled, the declared `f!` macro passes through the `const` keyword from the macro user to the final definition (`pub const unsafe extern fn foo`. When `extern-const-fn` is disabled, the `const` keyword passed by the macro user is discarded, resulting in a plain `pub extern const fn` being declared.
Unfortunately, I couldn't manage to get `macro_rules` to accept a normal `const` token in the proper place (after `pub`). I had to resort to placing it in curly brackets:
```rust
pub {const} fn foo(val: u8) -> i8 {
}
```
The `f!` macro then translates this to a function definition with `const` in the proper position.
I'd appreciate it if someone who's more familiar with `macro_rules!` could see if I missed a way to get the desired syntax.
sigevent structs on most platforms have padding or unused fields. Rather
than display those in the Debug impl by deriving it, manually implement
all extra_traits instead ignoring those fields.
Yuki Okushi
JohnTitor
Jonah Petri
Maarten de Vries
George Hopkins
LinkTed
Thomas de Zeeuw
Daniil Bondarev
Josh Triplett
Nikita Baksalyar
Gabriel Majeri
Bryan Donlan
Dan Gohman
Markus Reiter
Will
Benjamin Saunders
Vickenty Fesunov
Matthew McPherrin
bors
Arthur Gautier
Amanieu d'Antras
patrick felt
Aaron Hill
gnzlbg
Temirkhan Myrzamadi
Bryant Mairs