lifetime

This is what my code looks like. I'm trying to use a impled struct within my ShapeRenderer struct and use its methods. shapes.rs: use super::core::*; pub struct ShapeRenderer<'a> { core_renderer: &'a mut CanvasRenderer, } core.rs pub struct Canvas { pub width: usize, pub height: usize, pub array: Vec<char>, } pub struct Point { pub x: usize, pub y: usize, } pub struct CanvasRenderer<'a> { canvas: &'a mut Canvas, } impl<'a> CanvasRenderer<'a> { pub fn new(canvas: &'a mut Canvas) -> CanvasRenderer { CanvasRenderer { canvas: canvas } } } Error error[E0107]: wrong number of lifetime parameters:

I want to know how the exception object is created ? and why the handler function parameter can be a non-const reference? For example: class E{ public: const char * error; E(const char* arg):error(arg){ cout << "Constructor of E(): ";} E(const E& m){ cout << "Copy constructor E(E& m): " ; error=m.error; } }; int main(){ try{ throw E("Out of memory"); } catch(E& e){cout << e.error;} } Output: Constructor of E(): Out of memory so I have throw E("out of memory") and E("out of memory") is just a temporary object and no object has been created except E("out of memory") because no copy constructor

I have a small script that checks a large list of domains for their MX records, everything works fine but when the script finds a domain with no record, it takes quite a long time to skip to the next one. I have tried adding: query.lifetime = 1.0 or query.timeout = 1.0 but this doesn't seem to do anything. Does anyone know how this setting is configured? My script is below, thanks for your time. import dns.resolver from dns.exception import DNSException import dns.query import csv domains = csv.reader(open('domains.csv', 'rU')) output = open('output.txt', 'w') for row in domains: try: domain =

I'm confused about how to save a D3 selection for later use. In the code below, I have a "global" variable for my axes, to which I save them when they are first created. Later, I'm able to use this variable for certain things (here, setting some text) but not others (here, updating the scale), which only work if I explicitly (re)select the axes. Is there perhaps something about JavaScript variable scoping or lifetime that I don't understand? Any assistance is appreciated! The relevant code, much condensed from the full context : // Top level of page var gxaxis, gyaxis; var updatePlot =

This question already has an answer here: Why does the Rust compiler request I constrain a generic type parameter's lifetime (error E0309)? 1 answer Why is the bound `T: 'a` required in order to store a reference `&'a T`? 2 answers The compiler suggests I add a 'static lifetime because the parameter type may not live long enough, but I don't think that's what I want 2 answers I thought that I've got what the 'static lifetime is, but now I'm not sure. I'm trying to understand how to work with Tokio and Futures. My app is working, but the structure is awful, so I need to decompose it. Here comes