how to fix Out of memory error in c#

I created dll from c function and importing into c#

When I call the dll function I am getting error:

Unable to load DLL 'subFunction.dll': Not enough storage is available to process this command. (Exception from HRESULT: 0x80070008).

How to fix it.

I am inclined to say you look at it from the wrong side - this is not a C# issue, it is a simple as it is error in C++. I suggest you put up a native C++ command line test and check whether this happens there too, then you go on and fix your code.

Without debugging we are sort of guessing what you made wrong - and that will never work. BUt this seriously looks like C# is totally irrelevant for the question and it is a pure C level issue.