backtrace 0.3.5

A library to acquire a stack trace (backtrace) at runtime in a Rust program.
Documentation
extern crate backtrace;

fn main() {
    foo();
}

fn foo() { bar() }
fn bar() { baz() }
fn baz() { print() }

#[cfg(target_pointer_width = "32")] const HEX_WIDTH: usize = 10;
#[cfg(target_pointer_width = "64")] const HEX_WIDTH: usize = 20;

fn print() {
    let mut cnt = 0;
    backtrace::trace(|frame| {
        let ip = frame.ip();
        print!("frame #{:<2} - {:#02$x}", cnt, ip as usize, HEX_WIDTH);
        cnt += 1;

        let mut resolved = false;
        backtrace::resolve(frame.ip(), |symbol| {
            if !resolved {
                resolved = true;
            } else {
                print!("{}", vec![" "; 7 + 2 + 3 + HEX_WIDTH].join(""));
            }

            if let Some(name) = symbol.name() {
                print!(" - {}", name);
            } else {
                print!(" - <unknown>");
            }
            if let Some(file) = symbol.filename() {
                if let Some(l) = symbol.lineno() {
                    print!("\n{:13}{:4$}@ {}:{}", "", "", file.display(), l,
                           HEX_WIDTH);
                }
            }
            println!("");

        });
        if !resolved {
            println!(" - <no info>");
        }
        true // keep going
    });
}