extends error class

now accepts a custom message

fn_name and error code stored as class attributes

voicemeeterlib/error.py

@@ -5,6 +5,15 @@ class InstallError(Exception):
 class CAPIError(Exception):
     """Exception raised when the C-API returns error values"""
 
+    def __init__(self, fn_name, code, msg=None):
+        self.fn_name = fn_name
+        self.code = code
+        self.message = msg if msg else f"{fn_name} returned {code}"
+        super().__init__(self.message)
+
+    def __str__(self):
+        return f"{type(self).__name__}: {self.message}"
+
 
 class VMError(Exception):
     """Exception raised when general errors occur"""