Severe Memory leak

[Humrn]

I used it into my MFC project.But I found a lot of memory leaks when I stopped running the program.And I Only create a xlnt::workbook instance in my project without other operation(no load、no save 、 no read and no write operation).

[tfussell]

This sounds strange. xlnt should generally only use memory linear with the number of cells plus some base level of storage for shared objects like styles. Would you be able to use valgrind or something to find where the leak is? I've never really used MFC, but if you could create a minimal reproduction of this issue that would also be helpful.

[aewa-tech]

I had the same problem. I found 2 errors:

1 - In stylesheet.hpp, create_builtin_style function, names pointer is not deleted.
Solution:
Remove static from line
const auto *names = new std::unordered_map<std::size_t, std::string>

and delete names before exiting function.
delete names;
return new_style;

2 - In number_formats.cpp, in builtin_formats() function, formats pointer is not deleted.
I couldn't find a solution for this yet.

[tfussell]

There have been some long-standing performance issues with xlnt. I'm going to close all of the old issues in favor of a new umbrella issue #648 where we can discuss options to fix it.