Description
Windows binaries built with the -mwindows linker flag can't have any output to stdout or stderr in them or Windows will instantly terminate the program. I want to have windowed mode binaries for GUI applications, since without the windowed mode flag the binary will spawn a visible console window in addition to the GUI window every time it's run.
Panicing threads seem to cause an unconditional print to stderr. I'm trying to write a panic handler that will pop up a Windows message dialog instead of printing to stdout when the program terminates with a panic, but currently can't do that because windowed mode programs die at the point of the panic and the handler is never reached.
To test this, write panic.rs:
fn f() { panic!("This kills the Windows"); }
fn main() {
match std::thread::Builder::new().spawn(f).unwrap().join() {
Err(_) => { std::fs::File::create("panic_log.txt"); }
_ => {}
}
}Build it with rustc -C link-args=-mwindows panic.rs. Then run panic.exe from the Windows explorer. The program terminates and the panic_log.txt file never shows up. (It does seem to work if you run it from the Command Prompt, but end users will be clicking an icon.)