Exception handling mechanism for C++ function return values

The return value of a C function is undefined when an exception occurs, and the exception needs to be caught via a try-catch block and appropriate action taken: an exception is thrown only if the function cannot recover from the error. Use clear and meaningful exception types. Document exceptions that may be thrown in the function documentation. Use a try-catch block to catch exceptions and perform necessary actions.

Exception handling mechanism for C function return values

In C, functions can report error conditions by throwing exceptions. An exception is an event that interrupts the normal execution of a function and returns control to the caller. Functions can catch exceptions and take appropriate action through try-catch blocks.

Return values ​​and exceptions

The return value of a function is usually used to represent the result of function execution. However, when an exception occurs in a function, the return value has no effect. In this case, the function's return value is undefined.

Practical case

Consider the following function, which calculates the quotient of two integers:

int divide(int numerator, int denominator) {
  if (denominator == 0) {
    throw std::runtime_error("除数不能为零");
  }
  return numerator / denominator;
}

If the divide function is called If zero is passed as the denominator, the function throws a std::runtime_error exception. At this point, the function's return value is undefined.

Catch exceptions

Exceptions can be caught through the try-catch block. try blocks contain code that may throw exceptions. If an exception is thrown, execution control goes to the corresponding catch block.

try {
  int result = divide(10, 0);  // 会抛出异常
} catch (const std::exception& e) {
  std::cerr << "异常信息：" << e.what() << std::endl;
}

In the above example, the try block throws a divide-by-zero exception. catch block catches the exception and prints the exception information.

Exception types

C supports multiple exception types, including the built-in std::exception class and user-defined exception classes. Users can define their own exception classes and provide custom exception messages for them.

Best Practices

The following are best practices for handling function return value exceptions:

• Only if the function cannot recover from the error condition An exception is thrown when recovery occurs.
• Use specific and meaningful exception types.
• Record exceptions that may be thrown in the function documentation.
• Use try-catch blocks to catch exceptions and take appropriate action.

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