Add error handling for initialization failure.

speech-dispatcher/examples/hello_world.rs

@@ -1,13 +1,13 @@
 use speech_dispatcher::*;
 use std::io;
 
-fn main() {
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     let connection = speech_dispatcher::Connection::open(
         "hello_world",
         "hello_world",
         "hello_world",
         Mode::Threaded,
-    );
+    )?;
     connection.on_begin(Some(Box::new(|msg_id, client_id| {
         println!("Beginning {} from {}", msg_id, client_id)
     })));
@@ -36,4 +36,5 @@ fn main() {
     connection.set_punctuation(Punctuation::None);
     let mut _input = String::new();
     io::stdin().read_line(&mut _input).unwrap();
+    Ok(())
 }

speech-dispatcher/src/lib.rs

@@ -1,9 +1,12 @@
 #![allow(non_upper_case_globals)]
 
-use std::collections::HashMap;
-use std::ffi::{CStr, CString};
-use std::marker::Send;
-use std::sync::Mutex;
+use std::{
+    collections::HashMap,
+    ffi::{CStr, CString},
+    fmt,
+    marker::Send,
+    sync::Mutex,
+};
 
 use lazy_static::lazy_static;
 use speech_dispatcher_sys::*;
@@ -145,13 +148,29 @@ unsafe extern "C" fn cb_im(msg_id: u64, client_id: u64, state: u32, index_mark:
     }
 }
 
+#[derive(Debug)]
+pub enum SpeechDispatcherError {
+    InitializationError,
+}
+
+impl std::error::Error for SpeechDispatcherError {}
+
+impl fmt::Display for SpeechDispatcherError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        use SpeechDispatcherError::*;
+        match self {
+            InitializationError => write!(f, "Failed to initialize"),
+        }
+    }
+}
+
 impl Connection {
     pub fn open<S: Into<String>>(
         client_name: S,
         connection_name: S,
         user_name: S,
         mode: Mode,
-    ) -> Self {
+    ) -> Result<Self, SpeechDispatcherError> {
         let clientname = CString::new(client_name.into()).unwrap();
         let connectionname = CString::new(connection_name.into()).unwrap();
         let username = CString::new(user_name.into()).unwrap();
@@ -162,11 +181,19 @@ impl Connection {
                 username.as_ptr(),
                 mode as u32,
             );
-            Self::setup_connection(c)
+            if c.is_null() {
+                None
+            } else {
+                Some(Self::setup_connection(c))
+            }
         };
-        let mut c = Self(connection, 0);
-        c.setup();
-        c
+        if let Some(connection) = connection {
+            let mut c = Self(connection, 0);
+            c.setup();
+            Ok(c)
+        } else {
+            Err(SpeechDispatcherError::InitializationError)
+        }
     }
 
     pub unsafe fn open2<S: Into<String>>(