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+<h1 align="center">Exit Code Control</h1>
+<p align="center">
+    Managing program exit codes via the resource system
+</p>
+
+Providing the shell with a correct exit code when a program terminates is a basic CLI convention. Mingling offers a ready-to-use `ExitCodeSetup` that, together with the `ResExitCode` resource, makes exit code control incredibly simple.
+
+## Enabling ExitCodeSetup
+
+```rust
+@@@use mingling::prelude::*;
+@@@use mingling::setup::ExitCodeSetup;
+fn main() {
+    let mut program = ThisProgram::new();
+    program.with_setup(ExitCodeSetup::default());
+@@@ program.exec_and_exit();
+}
+```
+ 
+`ExitCodeSetup` does two things:
+
+1. Registers the `ResExitCode` resource (default value `0`)
+2. Registers a `finish` hook that reads the value of `ResExitCode` as the final exit code before the program exits
+
+## Modifying the Exit Code
+
+In a Chain or Renderer, inject `ResExitCode` to modify the exit code:
+
+```rust
+@@@use mingling::res::ResExitCode;
+@@@use mingling::setup::ExitCodeSetup;
+@@@pack!(EntryCheck = Vec<String>);
+#[chain]
+fn handle_check(_args: EntryCheck, ec: &mut ResExitCode) {
+    // Modify exit code when check fails
+    ec.exit_code = 1;
+}
+```
+ 
+> [!TIP]
+> `ResExitCode` is simply `struct ResExitCode { pub exit_code: i32 }`. Inject `&mut ResExitCode` and modify the field directly.
+
+## Three Execution Modes of `Program`
+
+`Program` provides three execution modes (excluding `exec_repl` under the `repl` feature):
+
+| Mode                            | Behavior                                                                                  |
+| ------------------------------- | ----------------------------------------------------------------------------------------- |
+| `program.exec_and_exit()`       | Executes and terminates the process directly with the exit code                           |
+| `program.exec()`                | Executes and returns an `i32` exit code, letting the caller decide handling               |
+| `program.exec_without_render()` | Returns `Result<RenderResult, ProgramExecuteError>`, with internal `exit_code` accessible |
+
+```rust
+@@@use mingling::setup::ExitCodeSetup;
+fn main() {
+    let mut program = ThisProgram::new();
+    program.with_setup(ExitCodeSetup::default());
+ 
+    // Get exit code and handle it yourself
+    let exit_code = program.exec();
+    std::process::exit(exit_code);
+}
+@@@gen_program!();
+```
+ 
+<p align="center" style="font-size: 0.85em; color: gray;">
+    Written by @Weicao-CatilGrass
+</p>