Help: why does the hello_world.rs example work

[FerrisWasTaken]

The code is after stripping the macos parts

use tts::*;

fn main() -> Result<(), Error> {
    let mut tts = Tts::default()?;
    if Tts::screen_reader_available() {
        println!("A screen reader is available on this platform.");
    } else {
        println!("No screen reader is available on this platform.");
    }
    let Features {
        utterance_callbacks,
        ..
    } = tts.supported_features();
    if utterance_callbacks {
        tts.on_utterance_begin(Some(Box::new(|utterance| {
            println!("Started speaking {:?}", utterance)
        })))?;
        tts.on_utterance_end(Some(Box::new(|utterance| {
            println!("Finished speaking {:?}", utterance)
        })))?;
        tts.on_utterance_stop(Some(Box::new(|utterance| {
            println!("Stopped speaking {:?}", utterance)
        })))?;
    }
    let Features { is_speaking, .. } = tts.supported_features();
    if is_speaking {
        println!("Are we speaking? {}", tts.is_speaking()?);
    }
    tts.speak("Hello, world.", false)?;
    let Features { rate, .. } = tts.supported_features();
    if rate {
        let original_rate = tts.get_rate()?;
        tts.speak(format!("Current rate: {}", original_rate), false)?;
        tts.set_rate(tts.max_rate())?;
        tts.speak("This is very fast.", false)?;
        tts.set_rate(tts.min_rate())?;
        tts.speak("This is very slow.", false)?;
        tts.set_rate(tts.normal_rate())?;
        tts.speak("This is the normal rate.", false)?;
        tts.set_rate(original_rate)?;
    }
    let Features { pitch, .. } = tts.supported_features();
    if pitch {
        let original_pitch = tts.get_pitch()?;
        tts.set_pitch(tts.max_pitch())?;
        tts.speak("This is high-pitch.", false)?;
        tts.set_pitch(tts.min_pitch())?;
        tts.speak("This is low pitch.", false)?;
        tts.set_pitch(tts.normal_pitch())?;
        tts.speak("This is normal pitch.", false)?;
        tts.set_pitch(original_pitch)?;
    }
    let Features { volume, .. } = tts.supported_features();
    if volume {
        let original_volume = tts.get_volume()?;
        tts.set_volume(tts.max_volume())?;
        tts.speak("This is loud!", false)?;
        tts.set_volume(tts.min_volume())?;
        tts.speak("This is quiet.", false)?;
        tts.set_volume(tts.normal_volume())?;
        tts.speak("This is normal volume.", false)?;
        tts.set_volume(original_volume)?;
    }
    let Features { voice, .. } = tts.supported_features();
    if voice {
        let voices = tts.voices()?;
        println!("Available voices:\n===");
        for v in &voices {
            println!("{:?}", v);
        }
        let Features { get_voice, .. } = tts.supported_features();
        let original_voice = if get_voice { tts.voice()? } else { None };
        for v in &voices {
            tts.set_voice(v)?;
            tts.speak(format!("This is {}.", v.name()), false)?;
        }
        if let Some(original_voice) = original_voice {
            tts.set_voice(&original_voice)?;
        }
    }
    tts.speak("Goodbye.", false)?;
    Ok(())
}

but when i strip it down to

use tts::*;

fn main() -> Result<(), Error> {
    let mut tts = Tts::default()?;
    tts.speak("Hello, world.", false)?;
    tts.speak("Goodbye.", false)?;
    Ok(())
}

No sound is generated NOTE: I have speechd installed on Linux.

[ndarilek]

The speech calls aren't blocking. You need that loop in the end to keep the program from exiting.

[FerrisWasTaken]

use tts::*;

fn main() -> Result<(), Error> {
    let mut tts = Tts::default()?;
    tts.speak("Hello, world.", false)?;
    let Features { voice, .. } = tts.supported_features();
    if voice {
        let voices = tts.voices()?;
        println!("Available voices:\n===");
        for v in &voices {
            println!("{:?}", v);
        }
        let Features { get_voice, .. } = tts.supported_features();
        let original_voice = if get_voice { tts.voice()? } else { None };
        for v in &voices {
            tts.set_voice(v)?;
            tts.speak(format!("This is {}.", v.name()), false)?;
        }
        if let Some(original_voice) = original_voice {
            tts.set_voice(&original_voice)?;
        }
    }
    tts.speak("Goodbye.", false)?;
    Ok(())
}

doesnt work. Can you send a minimal working example?

[ndarilek]

You've still got nothing to keep your program from exiting before everything speaks.

    let mut _input = String::new();
    // The below is only needed to make the example run on MacOS because there is no NSRunLoop in this context.
    // It shouldn't be needed in an app or game that almost certainly has one already.
    #[cfg(target_os = "macos")]
    {
        let run_loop: id = unsafe { NSRunLoop::currentRunLoop() };
        unsafe {
            let _: () = msg_send![run_loop, run];
        }
    }
    io::stdin().read_line(&mut _input)?;

[ndarilek]

No, it wouldn't, these calls are non-blocking and you've still got nothing to keep the program from exiting.

Why did you remove this? This is what's needed.

letmut_input= String::new();     // The below is only needed to make the example run on MacOS because there is no NSRunLoop in this context.     // It shouldn't be needed in an app or game that almost certainly has one already.     #[cfg(target_os = "macos")]     { letrunloop: id= unsafe{ NSRunLoop::currentRunLoop() }; unsafe{ let: () = msg_send![run_loop, run];         }     } io::stdin().read_line(&mut_input)?;