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ch 6.3.3 eprintln! macro in alloc produces endless alloc loop #119
Description
Running the graphical application to create and destroy objects on the heap (Listing 6.9)
creates an endless loop. (ManjaroLinux release: 24.1.1; rustc 1.81.0).
and stops with the error : 'cargo run' terminated by signal SIGSEGV (Address boundary error)
this happens when using a macro like eprintln! or format! etc.
println! makes the application hang.
With the help from https://users.rust-lang.org (link below) I found a workaround using extern "C" printf:
extern "C" {
fn printf(format: *const c_char, ...) -> c_int;
}
struct MyAllocator;
unsafe impl GlobalAlloc for MyAllocator {
unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
let start = Instant::now();
let ptr = System.alloc(layout);
let end = Instant::now();
let ellapsed = end - start;
let ellapsed_value = ellapsed.as_nanos();
let v = layout.size();
//eprint!("{}\t{}", v, ellapsed_value);
let format: *const c_char = c"%d\t%d \n".as_ptr().cast();
let _ = printf(format, v, ellapsed_value);
ptr
}
unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
System.dealloc(ptr, layout)
}
}
This works on my system. I don't know if it's still possible that it allocates on the heap for others.
Link to the issue on rust-org
Activity
niall-byrne commentedon Nov 25, 2024
I ran into a similar problem using rustc 1.82.0 (f6e511eec 2024-10-15).
The code would not execute, instead reporting:
Removing the macro call to
eprintln!resolved it, so I ended up following the same wormhole to create a C logger: