Hi Adam

Cant pretend to know what it all means but my udf procedure declarations end
in 'cdecl; export;'
could there be something there?

Regards
Paul

> -----Original Message-----
> From: firebird-support@yahoogroups.com
> [mailto:firebird-support@yahoogroups.com] On Behalf Of Adam
> Sent: 01 December 2008 03:19
> To: firebird-support@yahoogroups.com
> Subject: [firebird-support] UDF assistance
>
> 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$DATABASE;"
> query (even using the same values that result in the error.
>
> * 99.9% of the time, it works fine even under 2.1
> * The error does not occur until after the function has
> completed, as I receive FB_AddMins End in the debugger.
> * I have also tried changing the isc_decode_timestamp and
> isc_encode_timestamp to cdecl but it made no difference.
>
> The exact error message is:
> Statement failed, SQLCODE = -902
> Unable to complete network request to host "lappy".
> -Error reading data from the connection.
> -An existing connection was forcibly closed by the remote host.
>
> The function's purpose is to take a timestamp and a number of
> minutes, and to return a timestamp that many minutes later.
> (Yes, I know this particular function can also be done in
> PSQL). Can anyone see anything glaringly wrong with the code?
>
> TIA
> Adam
>
> (I have extracted the function into a new dll to simplify the
> required code, but I have confirmed the problem still occurs
> with this separate dll).
>
> Declaration:
> ============
>
> DECLARE EXTERNAL FUNCTION FB_ADDMINS
> TIMESTAMP,INTEGER
> RETURNS TIMESTAMP FREE_IT
> ENTRY_POINT 'FB_AddMins' MODULE_NAME 'MyUDF';
>
> UDF Code (Delphi 7):
> ==================
>
> library MyUDF;
>
> uses
> SysUtils,
> Classes,
> uMyUDF in 'uMyUDF.pas';
>
> {$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_timestamp(ib_date: PISC_TIMESTAMP;
> tm_date: PTM); stdcall; external 'gds32.dll'; procedure
> isc_encode_timestamp(tm_date: PTM; ib_date: PISC_TIMESTAMP);
> stdcall; external 'gds32.dll';
>
>
> function TimeStampToDateTime(TimeStamp: ISC_TIMESTAMP): TDateTime; var
> TempTM: TM;
> begin
> isc_decode_timestamp(@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_timestamp(@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.
>
>
>
>
> ------------------------------------
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