From 21ba68b41bf287965c50d62e1aaf0bf0e11a0d4f Mon Sep 17 00:00:00 2001
From: Dan Gohman <dev@sunfishcode.online>
Date: Fri, 23 Dec 2022 20:00:48 -0800
Subject: [PATCH] Implement `command` exit statuses. (#40)

Add a `result` return type to `command` so that it can indicate success
or failure.

The idea here is that this isn't a full `i32` return value because the
meaning of return values isn't portable across platforms. Also, Typed Main
is a better long-term answer for users that want rich error return
values from commands.
---
 src/lib.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/lib.rs b/src/lib.rs
index f8d99b45837f..5ad723e77266 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -33,7 +33,7 @@ pub unsafe extern "C" fn command(
     args_len: usize,
     env_vars: StrTupleList,
     preopens: PreopenList,
-) {
+) -> Result<(), ()> {
     // TODO: ideally turning off `command` would remove this import and the
     // `*.wit` metadata entirely but doing that ergonomically will likely
     // require some form of `use` to avoid duplicating lots of `*.wit` bits.
@@ -86,6 +86,7 @@ pub unsafe extern "C" fn command(
         fn _start();
     }
     _start();
+    Ok(())
 }
 
 // We're avoiding static initializers, so replace the standard assert macros