Use result of the computation to prevent the compiler from optimising
too much. Change `_x` to `x` and therefore remove the paragraph about
the underscore.
Fixes#25855.
These errors all relate to type checking, specifically the number of function arguments, and occur in librustc_typeck::check::check_argument_types.
Resolves part of #24407.
* Slate these features to be stable in 1.2 instead of 1.1 (not being backported)
* Have the `FromRawFd` implementations follow the contract of the `FromRawFd`
trait by taking ownership of the primitive specified.
* Refactor the implementations slightly to remove the `unreachable!` blocks as
well as separating the stdio representation of `std::process` from
`std::sys::process`.
cc #25494
Converts the size calculation in the explanation from a fenced code block to an indented one. I think it looks better when not rendered, and is the same rendered.
In the discussion of returning closures, it seems like the example code got simplified, but only the later copies got fixed. The final working code has `factory` returning `|x| x + num`, but the earlier code has `|x| vec.push(x)`.
The first form seemed to have more distracting characteristics, and the code wasn't right anyway, so I changed them to all use the second form, and updated the error messages.
r? @steveklabnik
These errors all relate to type checking, specifically the number of function arguments, and occur in librustc_typeck::check::check_argument_types.
Resolves part of #24407.
… congruent due to rounding errors
@semarie this affected both openbsd and bitrig. it seems the correct solution is to switch to fixed point arithmetic in the timeout code, the same as freebsd.
Various methods in both libcore/char.rs and librustc_unicode/char.rs were previously marked with #[inline], now every method is marked in char's impl blocks.
Partially fixes#26124.
EDIT: I'm not familiar with pull reqests (yet), apparently Github added my second commit to thit PR...
Fixes#26124
Implement RFC rust-lang/rfcs#1123
Add str method str::split_at(mid: usize) -> (&str, &str).
Also a minor cleanup in the collections::str module. Remove redundant slicing of self.
As far as I was able to determine, it's currently *impossible* to allocate a C NUL-terminated string in Rust and then return it to C (transferring ownership), without leaking memory. There is support for passing the string to C (borrowing).
To complicate matters, it's not possible for the C code to just call `free` on the allocated string, due to the different allocators in use.
`CString` has no way to recreate itself from a pointer. This commit adds one. This is complicated a bit because Rust `Vec`s want the pointer, size, and capacity.
To deal with that, another method to shrink and "leak" the `CString` to a `char *` is also provided.
We can then use `strlen` to determine the length of the string, which must match the capacity.
**TODO**
- [x] Improve documentation
- [x] Add stability markers
- [x] Convert to `Box<[u8]>`
### Example code
With this example code:
```rust
#![feature(libc)]
#![feature(cstr_to_str)]
#![feature(c_str_memory)]
extern crate libc;
use std::ffi::{CStr,CString};
#[no_mangle]
pub extern fn reverse(s: *const libc::c_char) -> *const libc::c_char {
let s = unsafe { CStr::from_ptr(s) };
let s2 = s.to_str().unwrap();
let s3: String = s2.chars().rev().collect();
let s4 = CString::new(s3).unwrap();
s4.into_ptr()
}
#[no_mangle]
pub extern fn cleanup(s: *const libc::c_char) {
unsafe { CString::from_ptr(s) };
}
```
Compiled using `rustc --crate-type dylib str.rs`, I was able to link against it from C (`gcc -L. -l str str.c -o str`):
```c
#include <stdio.h>
extern char *reverse(char *);
extern void cleanup(char *);
int main() {
char *s = reverse("Hello, world!");
printf("%s\n", s);
cleanup(s);
}
```
As well as dynamically link via Ruby:
```ruby
require 'fiddle'
require 'fiddle/import'
module LibSum
extend Fiddle::Importer
dlload './libstr.dylib'
extern 'char* reverse(char *)'
extern 'void cleanup(char *)'
end
s = LibSum.reverse("hello, world!")
puts s
LibSum.cleanup(s)
```
Doc patch for #26120. Extra words here, because "value" is repeated.
I haven't read about whether/how it should go to stable (sorry), but I think it would help newcomers.
Thanks,
