C-Language function invocation from another one.

Hi,

What is the best way to call C-Language function from another one?

Now I see only one method - to call SPI_execute("EXECUTE funcName(...);",
false, 0).
For example:

PG_FUNCTION_INFO_V1(calculateAccount);
PG_FUNCTION_INFO_V1(calculateAccountService);

Datum calculateAccount(PG_FUNCTION_ARGS);
Datum calculateAccountService(PG_FUNCTION_ARGS);

Datum calculateAccount(PG_FUNCTION_ARGS)
{
// Arguments
int32 accountId = PG_GETARG_INT32(0);
DateADT startDate = PG_GETARG_DATEADT(1);
DateADT endDate = PG_GETARG_DATEADT(2);
char command[1000];
...

SPI_connect();

snprintf(command, sizeof(command), "execute calculateAccountService(%d,
%d);", accountId, serviceId);
SPI_execute(command, false, 0);

SPI_finish();

PG_RETURN_NULL();
}

Datum calculateAccountService(PG_FUNCTION_ARGS)
{
int32 accountId = PG_GETARG_INT32(0);
int32 serviceId = PG_GETARG_INT32(1);

...

PG_RETURN_NULL();
}

--
Best regards,
Ilya Urikh.