How do I call a C function from C++?

How do I call a C function from C++?

Just declare the C function ``extern "C"'' (in your C++ code) and call it (from your C or C++ code). For example:

	// C++ code

	extern "C" void f(int);	// one way

	extern "C" {	// another way
		int g(double);
		double h();
	};

	void code(int i, double d)
	{
		f(i);
		int ii = g(d);
		double dd = h();
		// ...
	}

The definitions of the functions may look like this:

	/* C code: */

	void f(int i)
	{
		/* ... */
	}

	int g(double d)
	{
		/* ... */
	}

	double h()
	{
		/* ... */
	}

Note that C++ type rules, not C rules, are used. So you can't call function declared ``extern "C"'' with the wrong number of argument. For example:

	// C++ code

	void more_code(int i, double d)
	{
		double dd = h(i,d);	// error: unexpected arguments
		// ...
	}