Supported data types passed between C and C++

C data type	Equivalent C++ data type
char	char
signed char	signed char
unsigned char	unsigned char
short, signed short, short int, or signed short int	short, signed short, short int, or signed short int
unsigned short, or unsigned short int	unsigned short, or unsigned short int
int, signed, signed int	int, signed, signed int
unsigned, or unsigned int	unsigned, or unsigned int
long, signed long, long int, or signed long int	long, signed long, long int, or signed long int
unsigned long, or unsigned long int	unsigned long, or unsigned long int
float	float
double	double
long double	long double
struct	struct, some classes
union	union
enum	enum
array	array
pointers to above types, pointers to void	pointers to above types, reference variables of above types, or pointers to void
pointers to functions	pointers to functions
types created by typedef	types created by typedef

Note:

C functions invoked from C++ or C++ functions invoked from C must be declared as extern "C" in the C++ source.
Packed decimal is not supported by C++. If you need to use packed decimal data, declare and modify it in C code using C functions.
If C++ classes, using features that are not available in C (see Passing C++ objects for examples), are passed to C, the results are undefined.