What are the best practices for implementing fault-tolerant code in C++ using exception handling?

Best practices for implementing fault-tolerant code using exception handling in C++ include using custom exception types for specific error handling. An exception is thrown only if the error cannot be recovered. Use a constant variable to save the error message. Follow exception safety principles to ensure resource cleanup. Handle unknown exceptions, but use caution to avoid masking serious problems.

Best practices for implementing fault-tolerant code in C++ using exception handling

Exception handling is a method that separates error handling tasks from regular A powerful mechanism for separation in code flow. In C++, exceptions can be handled using the try-catch statement.

Best Practices:

• Use appropriate exception types: Create custom exception classes for specific error types instead of dependencies For the general std::exception.
• Throw exceptions only when necessary: ​​ Throw exceptions only when the code cannot recover from the error. For errors that can be easily handled, error codes or return codes are more appropriate.
• Use a const variable to save the error message: The error message should be static so that it does not change accidentally during exception propagation.
• Follow the exception safety principle: Ensure that functions that throw exceptions can safely clean up resources at any time.
• Handling unknown exceptions: Use the catch(...) statement to handle any exception type that is not specifically handled. However, it should be used with caution as it can mask potentially serious problems.

Practical case:

Suppose we have a function processFile(), which is used to read files and perform some processing. We can use exception handling to handle potential errors such as the file does not exist or cannot be read:

#include <iostream>
#include <fstream>
#include <stdexcept>

using namespace std;

struct FileReadError : runtime_error {
    FileReadError(const string& msg) : runtime_error(msg) {}
};

void processFile(const string& filename) {
    ifstream file(filename);
    if (!file.is_open()) {
        throw FileReadError("File not found or cannot be opened.");
    }

    // 在此处处理文件内容

    file.close();
}

int main() {
    try {
        processFile("input.txt");
    } catch (const FileReadError& e) {
        cout << "File read error: " << e.what() << endl;
    } catch (const exception& e) {
        cout << "Unknown exception occurred: " << e.what() << endl;
    }

    return 0;
}

In this example:

• FileReadError is a custom Exception type for errors specific to reading files.
• processFile() The function throws a FileReadError exception when the file cannot be opened. The
• main() function uses the try-catch statement to handle FileReadError and other exceptions that may occur.

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