SQL> connect 'inet4://localhost:3054/test' user SYSDBA password 'masterkey';
Database: 'inet4://localhost:3054/test', User: SYSDBA
SQL> SELECT CAST('00:00:00 Europe/Moscow' AS TIME WITH TIME ZONE),
CON>        CAST('00:00:00 +3' AS TIME WITH TIME ZONE) FROM RDB$DATABASE;

                                          CAST                                           CAST
============================================== ==============================================
00:00:00.0000 Europe/Moscow                    00:00:00.0000 +03:00

SQL>

void UtilInterface::decodeTime(ISC_TIME time,
	unsigned* hours, unsigned* minutes, unsigned* seconds, unsigned* fractions)
{
	tm times;
	isc_decode_sql_time(&time, &times);

	if (hours)
		*hours = times.tm_hour;
	if (minutes)
		*minutes = times.tm_min;
	if (seconds)
		*seconds = times.tm_sec;
	if (fractions)
		*fractions = time % ISC_TIME_SECONDS_PRECISION;
}

void UtilInterface::decodeTimeTz(CheckStatusWrapper* status, const ISC_TIME_TZ* timeTz,
	unsigned* hours, unsigned* minutes, unsigned* seconds, unsigned* fractions,
	unsigned timeZoneBufferLength, char* timeZoneBuffer)
{
	try
	{
		tm times;
		int intFractions;
		TimeZoneUtil::decodeTime(*timeTz, CVT_commonCallbacks, &times, &intFractions);

		if (hours)
			*hours = times.tm_hour;

		if (minutes)
			*minutes = times.tm_min;

		if (seconds)
			*seconds = times.tm_sec;

		if (fractions)
			*fractions = (unsigned) intFractions;

		if (timeZoneBuffer)
			TimeZoneUtil::format(timeZoneBuffer, timeZoneBufferLength, timeTz->time_zone);
	}
	catch (const Exception& ex)
	{
		ex.stuffException(status);
	}
}

select current_time from rdb$database

Error Message:
----------------------------------------
Access violation at address 6AEF917F in module 'fbclient.dll'. Read of address 00000004

[6AEF917F] isc_blob_set_desc + $465F
[00403BDF] System.@HandleAnyException + $33
[004F5BDE] Firebird.IUtil.decodeTimeTz (Line 253, "Firebird.pas" + 1) + $1E
[005345EC] FIBQuery.TFIBXSQLVAR.GetAsDateTime (Line 821, "FIBQuery.pas" + 30) + $30
[0052B8CC] FIBDataSet.TFIBCustomDataSet.FetchCurrentRecordToBuffer (Line 2276, "FIBDataSet.pas" + 69) + $E
[0052EBE7] FIBDataSet.TFIBCustomDataSet.GetRecord (Line 3991, "FIBDataSet.pas" + 50) + $16
[0050E152] Db.TDataSet.GetNextRecord (Line 9185, "DB.pas" + 9) + $13

SELECT
    CAST('12.12.2018 00:00:00 +4:00' AS TIMESTAMP WITH TIME ZONE)
   -- , current_timestamp as v
FROM
    RDB$DATABASE

SELECT
    CAST('12.12.2018 00:00:00 Africa/Asmera' AS TIMESTAMP WITH TIME ZONE)
FROM
    RDB$DATABASE

Use CONNECT or CREATE DATABASE to specify a database
SQL> connect 'inet4://localhost:3054/test' user sysdba password 'masterkey';
Database: 'inet4://localhost:3054/test', User: SYSDBA
SQL> select current_time from rdb$database;

                                  CURRENT_TIME
==============================================
18:06:50.0000 Europe/Moscow

SQL>

SQLCODE: -902
GDSCODE: 335545167

Unsuccessful execution caused by a system error that precludes successful execution of subsequent statements.
Could not find acceptable ICU library.
Missing entrypoint u_setDataDirectory in ICU library.

CREATE PROCEDURE P_EXCESS (A_ID INT, A_TRAN INT = NULL, A_CONN INT = NULL)
  RETURNS (ID INT, TRAN INT, CONN INT)
AS
DECLARE S VARCHAR(255);
DECLARE W VARCHAR(255) = '';
BEGIN
  S = 'SELECT * FROM TTT WHERE ID = :ID';

  IF (A_TRAN IS NOT NULL)
  THEN W = W || ' AND TRAN = :a';

  IF (A_CONN IS NOT NULL)
  THEN W = W || ' AND CONN = :b';

  IF (W <> '')
  THEN S = S || W;

  -- could raise error if TRAN or CONN is null
  -- FOR EXECUTE STATEMENT (:S) (a := :A_TRAN, b := A_CONN, id := A_ID)

  -- OK in all cases
  FOR EXECUTE STATEMENT (:S) (EXCESS a := :A_TRAN, EXCESS b := A_CONN, id := A_ID)
      INTO :ID, :TRAN, :CONN
      DO SUSPEND;
END

CREATE OR ALTER PACKAGE MY_PACKAGE
SQL SECURITY DEFINER
AS
BEGIN
-- выводит вот так
PROCEDURE FILL_MARE (
    CODE_ROLL   INTEGER,
    DATE_BEGIN  DATE,
    DATE_END    DATE);

    -- хочу чтобы у процедур и функций был отступ от края
    PROCEDURE FILL_STALL (
        CODE_ROLL   INTEGER,
        DATE_BEGIN  DATE,
        DATE_END    DATE);

END

interface DecFloat34 : Versioned
{
	const uint BCD_SIZE = 34;
	const uint STRING_SIZE = 43;	// includes terminating \0
	void toBcd(const FB_DEC34* from, int* sign, uchar* bcd, int* exp);
	void toString(Status status, const FB_DEC34* from, uint bufferLength, string buffer);
	void fromBcd(int sign, const uchar* bcd, int exp, FB_DEC34* to);
	void fromString(Status status, const string from, FB_DEC34* to);
}