diff --git a/Cargo.lock b/Cargo.lock
index f960839..a4928ce 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -214,7 +214,7 @@ dependencies = [
 
 [[package]]
 name = "stdin-nonblocking"
-version = "0.3.0"
+version = "0.4.0"
 dependencies = [
  "doc-comment",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index b9c0475..ea7b417 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "stdin-nonblocking"
-version = "0.3.0"
+version = "0.4.0"
 authors = ["Jeremy Harris <jeremy.harris@zenosmosis.com>"]
 description = "Dependency-less non-blocking stdin reader using background threads. Supports streaming and immediate fallback defaults."
 repository = "https://github.com/jzombie/rust-stdin-nonblocking"
diff --git a/README.md b/README.md
index 53413f2..beddc8e 100644
--- a/README.md
+++ b/README.md
@@ -34,7 +34,7 @@ use stdin_nonblocking::get_stdin_or_default;
 let input = get_stdin_or_default(Some(b"fallback_value"));
 
 // Input is always `Vec<u8>`, ensuring binary safety.
-assert_eq!(input, b"fallback_value".to_vec());
+assert_eq!(input, Some(b"fallback_value".to_vec()));
 ```
 
 ### Read `stdin` as Stream
diff --git a/src/bin/test_binary.rs b/src/bin/test_binary.rs
index 776215c..b60930e 100644
--- a/src/bin/test_binary.rs
+++ b/src/bin/test_binary.rs
@@ -7,6 +7,6 @@ fn main() {
 
     // Print raw binary data instead of Debug format
     io::stdout()
-        .write_all(&input)
+        .write_all(&input.unwrap())
         .expect("Failed to write output");
 }
diff --git a/src/lib.rs b/src/lib.rs
index 9f3f1b5..9d9a822 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,6 @@
+#[cfg(doctest)]
+doc_comment::doctest!("../README.md");
+
 use std::io::{self, IsTerminal, Read};
 use std::sync::mpsc::{self, Receiver, Sender};
 use std::thread;
@@ -77,7 +80,7 @@ pub fn spawn_stdin_stream() -> Receiver<Vec<u8>> {
 /// * `default` - An optional fallback value returned if no input is available.
 ///
 /// # Returns
-/// * `Vec<u8>` - The full stdin input (or default value as bytes).
+/// * `Option<Vec<u8>>` - The full stdin input (or default value as bytes).
 ///
 /// # Example
 /// ```
@@ -85,18 +88,21 @@ pub fn spawn_stdin_stream() -> Receiver<Vec<u8>> {
 ///
 /// let input = get_stdin_or_default(Some(b"fallback_value"));
 ///
-/// assert_eq!(input, b"fallback_value".to_vec());
+/// assert_eq!(input, Some(b"fallback_value".to_vec()));
 /// ```
-pub fn get_stdin_or_default(default: Option<&[u8]>) -> Vec<u8> {
+pub fn get_stdin_or_default(default: Option<&[u8]>) -> Option<Vec<u8>> {
     let stdin_channel = spawn_stdin_stream();
 
     // Give the reader thread a short time to capture any available input
     thread::sleep(Duration::from_millis(50));
 
     if let Ok(data) = stdin_channel.try_recv() {
-        return data;
+        return Some(data);
     }
 
+    // Return `None` if no default
+    default?;
+
     // No input available, return the default value
-    default.unwrap_or(b"").to_vec()
+    Some(default.unwrap_or(b"").to_vec())
 }