Yes, you can use C syntaxes when you are writing a program in C++. But for mixing codes successfully, the primary requirement is that your C and C++ compilers must be compatible. All C++ compilers support linking to C for some C-compatible compilers. For instance, the compilers must define fundamental types like int, float, and pointer in identical ways. The C++ programming language comes with a feature called linkage specification, using which you need to declare an object or function such that it adheres to the linkage conventions for the supported language kind. By default, the linkage setting for objects and functions in C++.