warning ignoring return value of ‘int scanf(const char from qnighy.hatenablog.com

Understanding the Benefits of Ignoring the Return Value of Functions Declared with warn_unused_result

What is warn_unused_result?

The warn_unused_result attribute is a GCC compiler attribute that informs the compiler that a particular function is expected to return a value, and that the value should not be ignored. It is typically used for functions that have side effects, such as I/O operations, and it is important to understand the implications of this attribute.

Why Should We Ignore the Return Value?

In some cases, it may be necessary to ignore the return value of a function declared with warn_unused_result. This could be due to the fact that the return value is not used in the code, or it could be due to the fact that the return value is not important. In either case, it is important to understand why it may be necessary to ignore the return value.

How to Ignore the Return Value

When ignoring the return value of a function declared with warn_unused_result, it is important to use the proper syntax. The syntax for ignoring the return value of a function is as follows: (void)function_name(); This will ensure that the compiler does not generate a warning when the return value is ignored.

The Benefits of Ignoring the Return Value

Ignoring the return value of a function declared with warn_unused_result can be beneficial in certain situations. It can help to reduce the amount of code necessary for a particular operation, as well as make the code more readable. Additionally, it can help to improve the performance of the code, as the compiler will not be generating a warning when the return value is not used.

Things to Consider When Ignoring the Return Value

When ignoring the return value of a function declared with warn_unused_result, it is important to consider the implications of doing so. For example, if the return value is important, then ignoring it could lead to unexpected results. Additionally, if the function has side effects, then ignoring the return value could cause those side effects to be missed.

Conclusion

Ignoring the return value of a function declared with warn_unused_result can be beneficial in certain situations. However, it is important to consider the implications of doing so, as it could lead to unexpected results. Additionally, it is important to use the proper syntax when ignoring the return value, as this will ensure that the compiler does not generate a warning.