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This article introduces the knowledge of why explicitly allocated resources are immediately handed over to resource management objects in C++. Many people will encounter this dilemma in the operation of actual cases. then let the editor lead you to learn how to deal with these situations! I hope you can read it carefully and be able to achieve something!

R.12: immediately hand over explicitly allocated resources to resource management objects

Reason (reason)

If you do not do so, a leak may occur when an exception occurs or when a return operation occurs.

Example, bad (negative example)

Void f (const string& name)

{

FILE* f = fopen (name, "r"); / / open the file

Vector buf (1024)

Auto _ = finally ([f] {fclose (f);}); / / remember to close the file

/ /...

}

Failure to allocate buffer (throw exception, translator's note) will cause the file handle to leak.

Example (sample)

Void f (const string& name)

{

Ifstream f {name}; / / open the file

Vector buf (1024)

/ /...

}

(managed with ifstream) the use of file handles is simple, efficient, and secure.

Enforcement (implementation recommendations)

Tag initializes pointers with explicitly allocated resources (the question is: how many cases can we identify when resources are allocated directly?)

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