Change origin_main's signature to avoid c_int.

Change `argc` to `usize` because a common use case is to pass it to
`slice::from_raw_parts`.

Change the return value to `i32`. This matches the type used by
`std::process::exit`.

Author: sunfishcode

example-crates/external-start/src/main.rs

@@ -56,7 +56,7 @@ static EARLY_INIT_ARRAY: unsafe extern "C" fn(i32, *mut *mut u8) = {
 };
 
 #[no_mangle]
-unsafe fn origin_main(_argc: i32, _argv: *mut *mut u8, _envp: *mut *mut u8) -> i32 {
+unsafe fn origin_main(_argc: usize, _argv: *mut *mut u8, _envp: *mut *mut u8) -> i32 {
     eprintln!("Hello from main thread");
 
     at_exit(Box::new(|| eprintln!("Hello from an at_exit handler")));

example-crates/origin-start-lto/src/main.rs

@@ -27,7 +27,7 @@ extern "C" fn eh_personality() {}
 static GLOBAL_ALLOCATOR: rustix_dlmalloc::GlobalDlmalloc = rustix_dlmalloc::GlobalDlmalloc;
 
 #[no_mangle]
-unsafe fn origin_main(_argc: i32, _argv: *mut *mut u8, _envp: *mut *mut u8) -> i32 {
+unsafe fn origin_main(_argc: usize, _argv: *mut *mut u8, _envp: *mut *mut u8) -> i32 {
     eprintln!("Hello from main thread");
 
     at_exit(Box::new(|| eprintln!("Hello from an at_exit handler")));

example-crates/origin-start-no-alloc/src/main.rs

@@ -21,7 +21,7 @@ fn panic(panic: &core::panic::PanicInfo<'_>) -> ! {
 extern "C" fn eh_personality() {}
 
 #[no_mangle]
-unsafe fn origin_main(_argc: i32, _argv: *mut *mut u8, _envp: *mut *mut u8) -> i32 {
+unsafe fn origin_main(_argc: usize, _argv: *mut *mut u8, _envp: *mut *mut u8) -> i32 {
     eprintln!("Hello!");
 
     // Unlike origin-start, this example can't create threads because origin's

example-crates/origin-start-tiny/src/main.rs

@@ -18,6 +18,6 @@ fn panic(_panic: &core::panic::PanicInfo<'_>) -> ! {
 extern "C" fn eh_personality() {}
 
 #[no_mangle]
-unsafe fn origin_main(_argc: i32, _argv: *mut *mut u8, _envp: *mut *mut u8) -> i32 {
+unsafe fn origin_main(_argc: usize, _argv: *mut *mut u8, _envp: *mut *mut u8) -> i32 {
     42
 }

example-crates/origin-start/src/main.rs

@@ -27,7 +27,7 @@ extern "C" fn eh_personality() {}
 static GLOBAL_ALLOCATOR: rustix_dlmalloc::GlobalDlmalloc = rustix_dlmalloc::GlobalDlmalloc;
 
 #[no_mangle]
-unsafe fn origin_main(_argc: i32, _argv: *mut *mut u8, _envp: *mut *mut u8) -> i32 {
+unsafe fn origin_main(_argc: usize, _argv: *mut *mut u8, _envp: *mut *mut u8) -> i32 {
     eprintln!("Hello from main thread");
 
     at_exit(Box::new(|| eprintln!("Hello from an at_exit handler")));

src/program.rs

@@ -118,7 +118,7 @@ unsafe fn init_runtime(mem: *mut usize, envp: *mut *mut u8) {
 #[allow(unused_variables)]
 unsafe fn call_user_code(argc: c_int, argv: *mut *mut u8, envp: *mut *mut u8) -> i32 {
     extern "Rust" {
-        fn origin_main(argc: c_int, argv: *mut *mut u8, envp: *mut *mut u8) -> c_int;
+        fn origin_main(argc: usize, argv: *mut *mut u8, envp: *mut *mut u8) -> i32;
     }
 
     // Call the functions registered via `.init_array`.
@@ -129,7 +129,7 @@ unsafe fn call_user_code(argc: c_int, argv: *mut *mut u8, envp: *mut *mut u8) ->
     log::trace!("Calling `origin_main({:?}, {:?}, {:?})`", argc, argv, envp);
 
     // Call `origin_main`.
-    let status = origin_main(argc, argv, envp);
+    let status = origin_main(argc as usize, argv, envp);
 
     #[cfg(feature = "log")]
     log::trace!("`origin_main` returned `{:?}`", status);