#include <postgres.h>
#include <fmgr.h>
#include <executor.h>

#ifdef PG_MODULE_MAGIC
	PG_MODULE_MAGIC;
#endif

PG_FUNCTION_INFO_V1(apr);
Datum apr(PG_FUNCTION_ARGS) {
	bool isnull;
	HeapTupleHeader  t = PG_GETARG_HEAPTUPLEHEADER(0);
	Datum d = GetAttributeByName(t, "t", &isnull);
	float4 r = DatumGetFloat8(d);
	PG_RETURN_FLOAT4(r);
}