Question
Answer and Explanation
A Message Compiler, often referred to as MC, is a tool used primarily in Windows development to manage application resources, especially strings and other data that need to be localized or accessed programmatically. What does it do?
The Message Compiler processes a message definition file (typically with a .mc extension). This file contains definitions for:
1. Message Identifiers: These are symbolic names associated with a message.
2. Message Text: The actual text of the messages, which can include formatting codes.
3. Severity Codes: Indications of the message's importance (e.g., informational, warning, error).
4. Facility Codes: Categorize messages based on the subsystem or component they belong to.
The Message Compiler takes the .mc file as input and generates several output files:
1. Header File (.h): Contains C/C++ definitions for the message identifiers, severity codes, and facility codes. This allows your code to refer to messages by symbolic names instead of hard-coded numbers.
2. Resource File (.rc): Contains the message text and other data in a format suitable for inclusion in a Windows application's resources.
3. Binary Message File (.bin): A binary version of the message resource. It can be used directly by the application, especially in scenarios where you want to load the message resources dynamically.
Here’s a basic example of what an .mc file might look like:
MessageIdTypedef=DWORD
SeverityNames=(Success=0x0:STATUS_SEVERITY_SUCCESS
Informational=0x1:STATUS_SEVERITY_INFORMATIONAL
Warning=0x2:STATUS_SEVERITY_WARNING
Error=0x3:STATUS_SEVERITY_ERROR
)
FacilityNames=(System=0x0:FACILITY_SYSTEM
Application=0x1:FACILITY_APPLICATION
)
MessageId=1
Severity=Informational
Facility=Application
SymbolName=MSG_APP_STARTED
Language=English
Application Started.%n
.
In C/C++ code, you would then use the generated header file to refer to MSG_APP_STARTED and retrieve the appropriate message text at runtime using functions like FormatMessage.
Benefits of using a Message Compiler:
1. Localization: Simplifies the process of localizing application messages, as the message text is separated from the code.
2. Maintainability: Improves code maintainability by using symbolic names for messages, making the code more readable and less prone to errors.
3. Resource Management: Centralizes message management and resource utilization.
In summary, the Message Compiler is a valuable tool for managing and organizing application messages in a structured and maintainable way, especially in Windows environments where resource management and localization are crucial.