#include "postgres.h"

#include "fmgr.h"

PG_MODULE_MAGIC;

Datum count_nulls(PG_FUNCTION_ARGS);

PG_FUNCTION_INFO_V1(count_nulls);
Datum
count_nulls(PG_FUNCTION_ARGS)
{
	int		nargs = PG_NARGS();
	int		num_nulls = 0;
	int		i;

	for (i = 0; i < nargs; i++)
	{
		if (PG_ARGISNULL(i))
			num_nulls++;
	}

	PG_RETURN_INT32(num_nulls);
}