Exit with non 0 exit code on failure

src/main.rs

@@ -1,6 +1,6 @@
 use compiler::{backend::spirv_meta, meta_compile};
 use error::print_error;
-use std::{env, fs, path::PathBuf};
+use std::{env, fs, path::PathBuf, process::ExitCode};
 
 use parser::parse_string;
 pub mod compiler;
@@ -17,7 +17,7 @@ struct CompilerArgs {
 
 const SPIRV_VERSION: &'static str = "1.0";
 
-fn main() {
+fn main() -> ExitCode {
     let args = parse_args();
     if args.print_version || args.print_help {
         if args.print_help {
@@ -26,12 +26,12 @@ fn main() {
         if args.print_version {
             print_version();
         }
-        return;
+        return ExitCode::FAILURE;
     }
 
     let Some(input) = args.input else {
         eprintln!("No input specified");
-        return;
+        return ExitCode::FAILURE;
     };
 
     let output = args.output.unwrap_or(PathBuf::from("./out.spv"));
@@ -40,7 +40,7 @@ fn main() {
         Ok(i) => i,
         Err(e) => {
             eprintln!("{e}");
-            return;
+            return ExitCode::FAILURE;
         }
     };
 
@@ -48,7 +48,7 @@ fn main() {
         Ok(i) => i,
         Err(e) => {
             print_error(e, Some(&src));
-            return;
+            return ExitCode::FAILURE;
         }
     };
 
@@ -56,13 +56,15 @@ fn main() {
         Ok(m) => m,
         Err(e) => {
             print_error(e, Some(&src));
-            return;
+            return ExitCode::FAILURE;
         }
     };
 
     let res = spirv_meta(module);
 
     fs::write(output, res).unwrap();
+
+    ExitCode::SUCCESS
 }
 
 fn parse_args() -> CompilerArgs {