Adam pisze:

>
>
> Hello Group,
>
> I am having some difficulty with a small number of UDF calls with
> Firebird 2.1.
>
> These have worked for years alongside Firebird 1.5. Furthermore, the
> problem is intermittent and difficult to reduce to a simple test case,
> as even removing an unrelated join from the query stops the error from
> occurring. I do have a reproducable test case, but it involves a 30
> line SQL statement and a 1GB database. I think it is better to rather
> start with the code I am using to see if there are any obvious errors.
> I have not been able to reproduce the error using "select
> FB_Addmins(' [some time literal]', [some integer]) from RDB$DATABASE; "
> query (even using the same values that result in the error.
>
> * 99.9% of the time, it works fine even under 2.1
> * The error does not occur until after the function has completed, as
> I receive FB_AddMins End in the debugger.
> * I have also tried changing the isc_decode_timestam p and
> isc_encode_timestam p to cdecl but it made no difference.
>
> The exact error message is:
> Statement failed, SQLCODE = -902
> Unable to complete network request to host "lappy".
> -Error reading data from the connection.
> -An existing connection was forcibly closed by the remote host.
>
> The function's purpose is to take a timestamp and a number of minutes,
> and to return a timestamp that many minutes later. (Yes, I know this
> particular function can also be done in PSQL). Can anyone see anything
> glaringly wrong with the code?
>
> TIA
> Adam
>
> (I have extracted the function into a new dll to simplify the required
> code, but I have confirmed the problem still occurs with this separate
> dll).
>
> Declaration:
> ============
>
> DECLARE EXTERNAL FUNCTION FB_ADDMINS
> TIMESTAMP,INTEGER
> RETURNS TIMESTAMP FREE_IT
> ENTRY_POINT 'FB_AddMins' MODULE_NAME 'MyUDF';
>
> UDF Code (Delphi 7):
> ============ ======
>
> library MyUDF;
>
> uses
> SysUtils,
> Classes,
> uMyUDF in 'uMyUDF.pas' ;
>
> {$R *.res}
>
> exports
>
> FB_AddMins;
>
> begin
> end.
>
> ------------ --------- --------- --------- ------
>
> unit uMyUDF;
>
> interface
>
> type
> Long = LongInt;
> ULong = Cardinal;
>
> ISC_TIMESTAMP = record
> timestamp_date : Long;
> timestamp_time : ULong;
> end;
>
> PISC_TIMESTAMP = ^ISC_TIMESTAMP;
>
> TM = record
> tm_sec : integer; // Seconds
> tm_min : integer; // Minutes
> tm_hour : integer; // Hour (0--23)
> tm_mday : integer; // Day of month (1--31)
> tm_mon : integer; // Month (0--11)
> tm_year : integer; // Year (calendar year minus 1900)
> tm_wday : integer; // Weekday (0--6) Sunday = 0)
> tm_yday : integer; // Day of year (0--365)
> tm_isdst : integer; // 0 if daylight savings time is not in effect)
> end;
>
> PTM = ^TM;
>
> function FB_AddMins(var DT: ISC_TIMESTAMP; var Minutes: Integer):
> PISC_TIMESTAMP; cdecl;
>
> implementation
>
> uses
> ibexternals,
> Windows,
> DateUtils;
>
> procedure isc_decode_timestam p(ib_date: PISC_TIMESTAMP; tm_date: PTM);
> stdcall; external 'gds32.dll';
> procedure isc_encode_timestam p(tm_date: PTM; ib_date: PISC_TIMESTAMP) ;
> stdcall; external 'gds32.dll';
>
> function TimeStampToDateTime (TimeStamp: ISC_TIMESTAMP) : TDateTime;
> var
> TempTM: TM;
> begin
> isc_decode_timestam p(@TimeStamp,
> @TempTM);
>
> Result := EncodeDateTime( TempTM.tm_ year+1900,
> TempTM.tm_mon+ 1,
> TempTM.tm_mday,
> TempTM.tm_hour,
> TempTM.tm_min,
> 0,
> 0);
> end;
>
> function DateTimeToTimeStamp (DateTime: TDateTime): ISC_TIMESTAMP;
> var
> Y,M,D,H,N,Dummy: Word;
> TempTM: TM;
> begin
> DecodeDateTime( DateTime,
> Y,
> M,
> D,
> H,
> N,
> Dummy,
> Dummy);
>
> TempTM.tm_year := Y - 1900;
> TempTM.tm_mon := M - 1;
> TempTM.tm_mday := D;
> TempTM.tm_hour := H;
> TempTM.tm_min := N;
> TempTM.tm_sec := 0;
>
> isc_encode_timestam p(@TempTM, @Result);
> end;
>
> {Export Functions}
>
> function FB_AddMins(var DT: ISC_TIMESTAMP; var Minutes: Integer):
> PISC_TIMESTAMP; cdecl;
> var
> DTConverted: TDateTime;
> begin
> OutputDebugString( 'FB_AddMins Start');
> DTConverted := TimeStampToDateTime (DT);
> DTConverted := DTConverted + Minutes/1440;
> DT := DateTimeToTimeStamp (DTConverted) ;
> Result := @DT;
> OutputDebugString( 'FB_AddMins End');
> end;
>
> end.
>

It may be not relevant, but must TIMESTAMP be released with FREE_IT ? I
see you are calling it as var param.


Regards
Boguslaw