Questions tagged [lifetime]
A variable's life-time is the time during which the variable is bound to a specific memory location. The life time starts when the variable is allocated and ends when it is deallocated.
lifetime
2,287
questions
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17
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Rust generic lifetime elision issue
I am trying to a implement generic observable collections for use with a UI framework I'm writing. I'm currently having an issue with lifetimes not being elidable in generics.
For brevity the ...
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votes
1
answer
42
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Lifetimes of &mut self inside Rust methods when asigning in an inner scope [duplicate]
The Context
I am trying to get wgpu to work with winit. I followed the winit v0.30 docs on how to create a window and am now trying to follow the learn wgpu tutorial that unfortunately uses wini v0.29 ...
- 9
0
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How to dynamically use plotter SegmentValue?
I have a struct Band:
pub struct Band{
pub name: String,
pub start_dt: NaiveDateTime,
pub end_dt: NaiveDateTime,
pub stage: String,
pub selected: bool,
}
I'm using the plotters ...
- 604
-1
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0
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37
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Lifetime of Temporary Passed to Multiple Functions by Const Reference in the Same Lexical Expression [duplicate]
According to the answers to this question, a temporary created in an expression lasts for the entire expression. This seems to imply that we can pass a temporary into and return it from functions by ...
- 127
2
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35
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Invariance of mutable references over their lifetimes [closed]
The Rustonomicon's chapter on subtyping and variance contains the passage
Also, we saw that it was not ok for us to treat &mut &'a U as a subtype of &mut &'b U, therefore we can say ...
- 2,442
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27
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Rust lifetimes in structs [duplicate]
Why is it not working?
struct Test<'s>(&'s mut i32);
impl<'n, 's: 'n> Test<'s> {
fn new(i: &'s mut i32) -> Self {
Self(i)
}
fn cast(&'s mut self) ...
- 73
3
votes
1
answer
61
views
Define lifetime for associative type without lifetime bound
I am implementing FromStr for a type and for the error I want to return the passed &str inside a wrapper struct. However, this requires the the struct to have a lifetime bound for the &str but ...
- 63
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1
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47
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rust [mockall return_once] borrowed value does not live long enough
I am learning Rust and I am writing a unit test using mockall library.
I have some String in my test and I want to pass it to multiple mock closures.
If I pass it directly, then I understand that I ...
- 501
0
votes
1
answer
62
views
Downcasting a type with a named lifetime parameter
I have the following code:
use std::any::Any;
use std::borrow::Cow;
// Base trait for downcasting
pub trait AsTranslationUnit<'a> {
fn as_any(&self) -> &dyn Any;
}
pub trait ...
- 2,049
0
votes
1
answer
44
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Returning and using an reqwest::Response from an async method
I am hoping to improve some logic that crafts and returns a Future for a reqwest::Response by adding in logic to catch, reauthenticate, and retry when the response is a 401. However, even before I get ...
- 1,748
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1
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109
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How to create a self referential struct?
Context: I'm working on a very fast algorithm to solve the Advent of Code 2023 Day 8 part 2 challenge without the least-common-multiple approach (which is meant to be impossible, hence the ...
- 582
1
vote
0
answers
70
views
Winking Out with polymorphic memory resources: efficient resource release and objects lifetime
I'm trying to understand "winking out" technique through examples (as I couldn't find, yet, a clean explanation). My goal is to acquire non-UB techniques that can be efficient when releasing ...
- 1,706
0
votes
1
answer
54
views
System.ObjectDisposedException: Cannot access a disposed context instance
I have a problem occurring when I execute:
await alarmHandler.InitRedis("setting");
System.ObjectDisposedException: Cannot access a disposed context instance. A common cause of this error ...
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0
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45
views
implementation of trait is not general enough
Let's say I have access to the following functions:
trait T<'a> {}
impl<'a> T<'a> for &'a str {}
fn takes_fn(f: impl Fn(&str)) {}
fn take_both<'a, X:T<'a>>(a: &...
- 6,715
1
vote
0
answers
21
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Understanding lifetime across async [duplicate]
I have this rust program:
// src/main.rs
#![feature(async_closure)]
use std::error::Error;
use std::future::Future;
struct Foo {
data: String,
}
impl Foo {
pub async fn show<J, F>(&...
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