C++ function call safety: avoid parameter errors and return value traps

When calling a function in C, to avoid parameter errors and return value traps, you need to follow the following steps: Use type-safe parameter types and perform range checking to avoid parameter errors. Use error return codes and handle errors correctly to avoid return value traps. Make sure function prototypes and calls are consistent with parameter types and return values. Use debugging tools to detect parameter errors.

C function call safety: avoid parameter errors and return value traps

When calling a function in C, ensure that the parameters are passed and Correct handling of return values ​​is critical. Neglecting these aspects can lead to subtle bugs and runtime anomalies.

Avoid parameter errors

Parameter errors usually arise from the following reasons:

• Passing parameters of the wrong type
• Passing Invalid range value
• Forgot to pass required parameter

Solution:

• Use type-safe parameter types, such as const, enum and templates.
• Check the range value and throw an exception if out of bounds.
• By overloading the function, the caller is forced to pass all necessary parameters.

Practical case:

void SetSize(int width, int height) {
  if (width <= 0 || height <= 0)
    throw std::invalid_argument("Size must be positive");
  _width = width;
  _height = height;
}

In this function, we use the type safety parameter type (int) to perform range checking, and throws an exception to handle invalid input.

Handling return value traps

If a function does not handle return values ​​correctly, it may cause serious problems. Common pitfalls include:

• Ignore error return codes
• Assume the function always executes successfully

Solution:

• Use error return codes and handle errors accordingly.
• Use the noexcept keyword to declare a function that does not throw exceptions.

Practical case:

int LoadFile(const std::string& filename) {
  std::ifstream file(filename);
  if (!file.is_open())
    return -1;  // 文件打开失败
  // ...读取文件并返回错误代码
  return 0;
}

This function uses the error return code (-1) to indicate the failure to open the file, and Declaring it will not throw an exception via the noexcept keyword.

Note:

• Ensure that function prototypes and calls are consistent with parameter types and return values.
• Use good documentation and comments to clearly define the semantics of parameters and return values.
• Consider using a debugging tool, such as Valgrind, to detect parameter errors.

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