diff --git a/lib/std/libc/libc.c3 b/lib/std/libc/libc.c3
index 1f1a6aeb1..f21c6df5e 100644
--- a/lib/std/libc/libc.c3
+++ b/lib/std/libc/libc.c3
@@ -97,6 +97,7 @@ extern fn CInt close(CInt fd) @if(!env::WIN32);
 extern fn double difftime(Time_t time1, Time_t time2) @if(!env::WIN32);
 extern fn DivResult div(CInt numer, CInt denom);
 extern fn void exit(CInt status);
+extern fn void _exit(CInt status) @extern("_Exit");
 extern fn CInt fclose(CFile stream);
 extern fn CFile fdopen(CInt fd, ZString mode) @if(!env::WIN32);
 extern fn CInt feof(CFile stream);
diff --git a/lib/std/libc/os/errno.c3 b/lib/std/libc/os/errno.c3
index c5db365f9..1fb2ec008 100644
--- a/lib/std/libc/os/errno.c3
+++ b/lib/std/libc/os/errno.c3
@@ -1,4 +1,4 @@
-module libc::os;
+module libc::os @if(env::LIBC);
 
 // Linux
 extern fn int* __errno_location() @if(env::LINUX);
@@ -22,7 +22,7 @@ extern fn void _get_errno(int* result) @if(env::WIN32);
 extern fn void _set_errno(int err) @if(env::WIN32);
 
 // Default
-const ERRNO_DEFAULT @local = !env::LINUX && !env::DARWIN && !env::WIN32;
-tlocal int _errno_c3 @if(ERRNO_DEFAULT) = 0;
-fn void errno_set(int err) @if(ERRNO_DEFAULT) => _errno_c3 = err;
-fn int errno() @if(ERRNO_DEFAULT) => _errno_c3;
+module libc::os @if(!env::LIBC || !(env::LINUX || env::DARWIN || env::WIN32));
+tlocal int _errno_c3 = 0;
+fn void errno_set(int err) => _errno_c3 = err;
+fn int errno() => _errno_c3;
diff --git a/lib/std/os/os.c3 b/lib/std/os/os.c3
new file mode 100644
index 000000000..e7cab9a6d
--- /dev/null
+++ b/lib/std/os/os.c3
@@ -0,0 +1,27 @@
+module std::os;
+import libc;
+
+<*
+ Exit the process with a given exit code. This will typically call 'exit' in LibC
+*>
+fn void exit(int result, bool cleanup = true) @weak
+{
+	$if env::LIBC:
+		libc::exit(result);
+	$else
+		$$trap();
+	$endif
+}
+
+<*
+ Exit the process with a given exit code. This will typically call '_Exit' in LibC
+ usually bypassing '@finalizer' functions.
+*>
+fn void fastexit(int result, bool cleanup = true) @weak
+{
+	$if env::LIBC:
+		libc::_exit(result);
+	$else
+		$$trap();
+	$endif
+}
diff --git a/releasenotes.md b/releasenotes.md
index 3a4ff6241..96210899f 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -75,6 +75,7 @@
 - `AnyList` now also defaults to the temp allocator.
 - `os::getcwd` and `os::get_home_dir` requires an explicit allocator.
 - `file::load_new` and `file::load_path_new` removed.
+- `os::exit` and `os::fastexit` added.
 
 ## 0.6.8 Change list
 
diff --git a/test/src/test_suite_runner.c3 b/test/src/test_suite_runner.c3
index e6dc3b31e..96437346d 100644
--- a/test/src/test_suite_runner.c3
+++ b/test/src/test_suite_runner.c3
@@ -86,7 +86,7 @@ fn void main(String[] args)
 	io::printfn("Found %d tests: %.1f%% (%d / %d) passed (%d skipped).",
         test_count, (100.0 * success_count) / math::max(1, test_count - skip_count),
         success_count, test_count - skip_count, skip_count);
-    libc::exit(success_count == test_count - skip_count ? 0 :  1);
+    os::exit(success_count == test_count - skip_count ? 0 :  1);
 }
 
 struct Error
@@ -346,7 +346,7 @@ fn void parse_header_directive(int* line_no, String line, RunSettings* settings,
 			settings.output_files.push(file);
 		default:
 			io::printfn("FAILED - Unknown header directive '%s'", line);
-			libc::exit(1);
+			os::exit(1);
 	}
 }
 
@@ -528,7 +528,7 @@ fn void usage(String appname) @noreturn
     io::printn("Options:");
     io::printn("  -s, --skipped       only run skipped tests");
     io::printn("  --stdlib <path>     override the path to stdlib");
-	libc::exit(0);
+	os::exit(0);
 }
 
 fn void arg_error_exit(String appname, String fmt, args...) @noreturn