Valgrind内存泄漏

Question

Record* MyClass::get_record (int id)
{
    Record* rec = new Record();
    Record* compressed_rec;

    /* ... code that gets compressed_rec into memory ... */

    compressed_rec->decompress(rec);

    return rec;
}

This function is always used like this:

Record* rec = my_class_instance.get_record (id);
show_contents_of(rec);
delete rec;

valgrind says that i'm leaking memory on the first line ( Record* rec = new Record(); ). Why?

Answer 1

valgrind says that i'm leaking memory on the first line (Record* rec = new Record();). Why?

Does it show the Record itself is being leaked, or something else allocated inside Record::Record ?

If the former, either some return path from MyClass::get_record leaks it, or the caller leaks it. Switching to use a smart pointer would fix both cases:

std::unique_ptr<Record> MyClass::get_record (int id)
{
    std::unique_ptr<Record> rec(new Record());
    ...
    return rec;
}

If it's the latter case, that either means the whole Record is being leaked (see above), or its destructor is buggy. Again, try keeping any dynamically allocated members in smart pointers.