How to Use Rust .lib file in keil

i have developed a code and add a method “AddTwoNo()” in that code and i build it and get static library file (.lib) . but when i use in keil software it return " Not Define AddTwoNo() Method" , i already given declaration of the same method in .H file .

Note:Keil is using other .lib files .
Can any one help me to solve it , is .lib files have more than one format?

Did you put your Rust function into an extern {} block?
Otherwise the Rust compiler will mangle the name of the function and so it will not be called AddTwoNo() in the resulting library file anymore (the same happens with C++ so you need to declare C++ functions as extern "C" if you want to call them from non-C++).