Is it possible to print a backtrace in Rust without panicking?
Solution 1:
Rust uses the backtrace crate to print the backtrace in case of panics (has been merged in PR #60852).
A simple example can be found in the crate documentation
use backtrace::Backtrace;
fn main() {
let bt = Backtrace::new();
// do_some_work();
println!("{:?}", bt);
}
which gives for example
stack backtrace:
0: playground::main::h6849180917e9510b (0x55baf1676201)
at src/main.rs:4
1: std::rt::lang_start::{{closure}}::hb3ceb20351fe39ee (0x55baf1675faf)
at /rustc/3c235d5600393dfe6c36eeed34042efad8d4f26e/src/libstd/rt.rs:64
2: {{closure}} (0x55baf16be492)
at src/libstd/rt.rs:49
do_call<closure,i32>
at src/libstd/panicking.rs:293
3: __rust_maybe_catch_panic (0x55baf16c00b9)
at src/libpanic_unwind/lib.rs:87
4: try<i32,closure> (0x55baf16bef9c)
at src/libstd/panicking.rs:272
catch_unwind<closure,i32>
at src/libstd/panic.rs:388
lang_start_internal
at src/libstd/rt.rs:48
5: std::rt::lang_start::h2c4217f9057b6ddb (0x55baf1675f88)
at /rustc/3c235d5600393dfe6c36eeed34042efad8d4f26e/src/libstd/rt.rs:64
6: main (0x55baf16762f9)
7: __libc_start_main (0x7fab051b9b96)
8: _start (0x55baf1675e59)
9: <unknown> (0x0)
Solution 2:
There is a custom feature backtrace
available, which allows one to print backtraces through std on nightly
rust.
Example:
#![feature(backtrace)]
use std::backtrace::Backtrace;
fn main() {
println!("Custom backtrace: {}", Backtrace::capture());
// ... or forcibly capture bt regardless of environment variable configuration
println!("Custom backtrace: {}", Backtrace::force_capture());
}
Documentation: https://doc.rust-lang.org/std/backtrace/struct.Backtrace.html
The backtrace module was added in https://github.com/rust-lang/rust/pull/64154. See the tracking issue for unstable feature: https://github.com/rust-lang/rust/issues/53487