refactor: rename project name from underline to dash

wfassoc-cdylib/src/last_error.rs

@@ -0,0 +1,58 @@
+//! When calling function with dynamic library,
+//! function return value indicates whether function has been successfully executed.
+//! When function return `false`, programmer may want to know which error occurs.
+//! 
+//! This module provide **thread independent** error message string storage,
+//! which is more like Win32 `GetLastError()` but return error message instead of error code.
+//! These module provided functions will be called when executing main module functions.
+
+use std::cell::RefCell;
+use std::ffi::{CString, c_char};
+
+struct LastError {
+    msg: CString,
+}
+
+impl LastError {
+    fn new() -> Self {
+        Self {
+            msg: CString::new("").expect("empty string must be valid for CString"),
+        }
+    }
+
+    pub fn set_msg(&mut self, msg: &str) {
+        self.msg = CString::new(msg).expect("unexpected blank in error message output");
+    }
+
+    pub fn get_msg(&self) -> *const c_char {
+        self.msg.as_ptr()
+    }
+
+    pub fn clear_msg(&mut self) {
+        self.msg = CString::new("").expect("empty string must be valid for CString");
+    }
+}
+
+thread_local! {
+    static LAST_ERROR: RefCell<LastError> = RefCell::new(LastError::new());
+}
+
+/// Set thread local error message.
+pub fn set_last_error(msg: &str) {
+    LAST_ERROR.with(|e| {
+        e.borrow_mut().set_msg(msg);
+    });
+}
+
+/// Get const pointer to thread local error message string.
+/// If there is no error, return pointer will point to empty string.
+pub fn get_last_error() -> *const c_char {
+    LAST_ERROR.with(|e| e.borrow().get_msg())
+}
+
+/// Clear thread local error message (reset to empty string).
+pub fn clear_last_error() {
+    LAST_ERROR.with(|e| {
+        e.borrow_mut().clear_msg();
+    });
+}