Search Results

Search found 5657 results on 227 pages for 'delphi 2007'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 99/227 | < Previous Page | 95 96 97 98 99 100 101 102 103 104 105 106  | Next Page >

  • Delphi - Why does ExplicitWidth and ExplicitHeight keep appearing in .DFM files and what is it!?

    - by Pauk
    We've noticed that when checking in updates that our .DFM files have had ExplicitWidth and ExplicitHeight properties added for what appears to be no particular reason. My two questions are, what are they for and why do they get automatically added by Delphi? Below is an example with the property in: object Splitter2: TcxSplitter Left = 0 Top = 292 Width = 566 Height = 8 Cursor = crVSplit HotZoneClassName = 'TcxXPTaskBarStyle' AlignSplitter = salBottom Control = BottomPanel Color = clBtnFace ExplicitWidth = 8 end

    Read the article

  • Should I move from Java programming to Delphi programming?

    - by Everyone
    over the years i have been employed in a permanent position with firms that did their development work in Windows SDK, VC++, and most recently Java; in my own eyes, I am language independent. Should I move from Java to Delphi (assuming pay-scale remains unchanged)? I'm concerned because, for the most part, the net presents a relatively bleak picture for this particular skill.

    Read the article

  • How to open webpage in HIDDEN default browser? DELPHI

    - by obma
    I have been trying to open a hidden default browser from delphi but coulnd't. I tried ShellExecute(self.WindowHandle,'open','www.google.com',nil,nil, SW_HIDE); and I get my chrome browser open but not hidden, and it opens a tab not a new window, also tried with TStartupInfo with the same results. Is there another way to achieve this?

    Read the article

  • Delphi plugin for pasting text constants in source code?

    - by mjn
    Inserting (pasting from clipboard) of text constants in the Delphi code editor requires some manual "postprocessing" ... split up long text into multiple lines (and insert the string concatenation symbol) escape quotes (replace single quotes with double quotes) enclose the string with quotes keep original white space (leadinng blanks, line feeds) Is there a IDE plugin available which helps to reduce these manual steps?

    Read the article

  • How to generate unique serial number of machine in Delphi?

    - by noxwow
    Hi, I have question how to generate unique serial number of machine in Delphi? I tried to do this using the ID the motherboard or processor, but unfortunately it's unfortunately supported. Partition serial numbers, etc. fall off, because it is changing after the formatted. I'm looking for something that doesn't change after the formatted. Has anyone any idea?

    Read the article

  • How to make a system time-zone sensitive?

    - by Jerry Dodge
    I need to implement time zones in a very large and old Delphi system, where there's a central SQL Server database and possibly hundreds of client installations around the world in different time zones. The application already interacts with the database by only using the date/time of the database server. So, all the time stamps saved in both the database and on the client machines are the date/time of the database server when it happened, never the time of the client machine. So, when a client is about to display the date/time of something (such as a transaction) which is coming from this database, it needs to show the date/time converted to the local time zone. This is where I get lost. I would naturally assume there should be something in SQL to recognize the time zone and convert a DateTime field dynamically. I'm not sure if such a thing exists though. If so, that would be perfect, but if not, I need to figure out another way. This Delphi system (multiple projects) utilizes the SQL Server database using ADO components, VCL data-aware controls, and QuickReports (using data sources). So, there's many places where the data goes directly from the database query to rendering on the screen, without any code to actually put this data on the screen. In the end, I need to know when and how should I get the properly converted time? There must be a standard method for this, and I'm hoping SQL Server 2008 R2 has this covered...

    Read the article

  • How to make a legacy system time-zone sensitive?

    - by Jerry Dodge
    I need to implement time zones in a very large and old Delphi system, where there's a central SQL Server database and possibly hundreds of client installations around the world in different time zones. The application already interacts with the database by only using the date/time of the database server. So, all the time stamps saved in both the database and on the client machines are the date/time of the database server when it happened, never the time of the client machine. So, when a client is about to display the date/time of something (such as a transaction) which is coming from this database, it needs to show the date/time converted to the local time zone. This is where I get lost. I would naturally assume there should be something in SQL to recognize the time zone and convert a DateTime field dynamically. I'm not sure if such a thing exists though. If so, that would be perfect, but if not, I need to figure out another way. This Delphi system (multiple projects) utilizes the SQL Server database using ADO components, VCL data-aware controls, and QuickReports (using data sources). So, there's many places where the data goes directly from the database query to rendering on the screen, without any code to actually put this data on the screen. In the end, I need to know when and how should I get the properly converted time? What is the proper way to ensure that I handle Dates and Times correctly in a legacy application?

    Read the article

  • How to access an encrypted INI file from C on an embedded system with little RAM

    - by Mawg
    I want to encrypt an INI file using a Delphi program on a Windows PC. Then I need to decrypt & access it in C on an embedded system with little RAM. I will do that once & fetch all info; I will not be consutinuously accessing the INI file whenever my program needs data from the file. Any advice as to which encryption to use? Nothing too heavyweight, just good enough for "Security through obscurity" and FOSS for both Delphi & C. And how can I decrypt, get all the info from the INI file - using as little RAM as possible, and then free any allocated RAM? I hope that someone can help. [Update] I am currently using an Atmel UC3, although I am not sure if that will be the final case. It has 512kB falsh & 128kB RAM. For an INI file, I am talking of max 8 sections, with a total of max 256 entries, each max 8 chars. I chose INI (but am not married to it), because i have had major problems in the past when the format of a data fiel changes, no matter whether binary, or text. For tex, I prefer the free format of INI (on PC), but suppose I could switch to line_1=data_1, line_2=data_2 and accept that if I add new fields in future software erleases they must come at the end, even if it is not pretty when read directly by humans. I suppose if I choose a fixed format text file then I never need get more than one line into RAM at a time ...

    Read the article

  • Is there a precedent for the license on a compiler restricting the kind of development you can use it for?

    - by Jim McKeeth
    It was recently let slip that the new EULA for Delphi XE3 will prohibit Client Server development with the Professional edition without the additional purchase of a Client Server license pack. This is not to say the Professional version will lack the features, but the license will specifically prohibit the developer from using the compiler for a specific class of development, even with 3rd party or home grown solutions. So my question is if there is a precedent of a compiler or similar creative tool prohibiting the class of work you can use it for. Specifically a commercially licensed "professional" tool like Delphi XE3. Also, would such a restriction be legally enforceable? I know there have been educational edition or starter edition tools in the past that have restricted their use for commercial purposes, but those were not sold as "professional" tools. Also I know that a lot of computing software and equipment will have a disclaimer that it is not for use in "life support equipment" or "nuclear power" but that is more of avoiding liability than prohibiting activity. Seems like I recall Microsoft putting a restriction in FrontPage that you couldn't use it to create a web site that reflected poorly on Microsoft, but they pulled that restriction before it could be tested legally.

    Read the article

  • rfid programming

    - by MaKo
    hi guys, I got a gift from a friend, 2 readers for RFID, and some cards (from a Chinese company called daily rfid), the kind of work, because it comes with some demo software written in Delphi, that reads the id of the card (myfare compatible, ISO14443A ) but the problem is that if I try to use the demo to write to them, it doesnt seem to work, it have another demo written in c#, (compiled and executable from /bin/debug, the DL600DemoCSharp.exe), the software opens, but when click on connect, I get this error Unhanded exception.. unable to load DLL 'BasicB.DLL' so I load the dll on windows/system32, but when I try regsvr32 BasicB.dll I get, error the module "BasicB.dll" was loaded but hte entry-point DllRegisterServer was not found. Make sure that "BasicB.dll" is a valid DLL or OCX file and then try again have written to the company but no response, I program in objective C, so I kind of understand c#, but how to make this cards work? - shall I continue with the delphi, and try to write to them with it - or with c# - either way I would have to write the code to read write to them,, or is there any software to work with this modules?? thanks a lot!

    Read the article

  • How to call a .NET COM method with an array from delphi using PSafeArray?

    - by Sebastian Godelet
    Hello. I have an .NET (4.0) interface which is implemented with a ServicedComponent COM+ class: interface DotNetIface { void MethodRef(var System.Guid guid); void MethodArray(System.Guid[] guids, params object[] parameters); void MethodCStyle([MarshalAs(UnmanagedType.LPArray, ArraySubType=UnmanagedType.Struct, SizeConst=5)]System.Guid[] guids); } Now I used the Delphi 2007 import wizard to import the type library, and as expected I get the following signatures: procedure MethodRef(var guid : TGuid); procedure MethodArray(guids : PSafeArray); procedure MethodCStyle(var guids : ClrGuid /* from mscorlib_TLB */); If i now call the "ref" method like this it works fine: procedure CallByRef(guid : TGuid); var test : TGuid; begin test := ... comRef.MethodRef(guid); end; Now I also need the array method procedure CallArray(); var localGuid : TGuid; arrayVariant : OleVariant; begin arrayVariant := VarArrayCreate([0,4], varVariant /* dont know here */); arrayVariant[0] := localGuid; /* compile error, cannot cast implicitly */ comRef.MethodArray(PSafeArray(TVarData(arrayVariant.VArray)), /* here this object... PSafeArray works actually*/); end; Now lastly i tried with a c array procedure CallCStyle(); var localGuid : TGuid; arrayOfGuid : array [0..4] of ClrGuid; begin arrayOfGuid[0] := ClrGuid(localGuid); comRef.MethodCStyle(PSafeArray(/* now i dont know put it*/, /* here this object... PSafeArray works actually*/); end; I seriously dont know how to make this work. I hope someone has more experience with COM marshalling thx Side node: I found VT_CLSID which i think can be passed for SafeArrayCreate, but I am not sure how to sue that

    Read the article

  • MOSS 2007 &ndash; WCM Blank WebPart Page Zone ID&rsquo;s

    - by Jeff Julian
    Here is the list of Zone ID’s for the Blank WebPart Page (BlankWebPartPage.aspx") that is part of the Publishing Portal with MOSS 2007: TitleBar Header TopLeftRow TopRightRow CenterLeftColumn CenterColumn CenterRightColumn Footer RightColumn I was in need of these and wasn’t able to find them with a simple search on Google so I wanted to share them with you. To get a list of WebPartZone objects for a page that a webpart lives on can be done with the following code:  foreach (WebPartZone zone in this.WebPartManager.Zones) {          this.Controls.Add(new LiteralControl(zone.ID + "<br />")); } Use this code in a webpart that inherits from Microsoft.SharePoint.WebPartPages.WebPart. This is a simple way to do the equivalent of a Response.Write while having the output in the webpart zone your part resides in.  It also saves you from attaching to the process and debugging with the watch or quick watch. Technorati Tags: MOSS,WebParts,BlankWebPartPage.aspx,Zones

    Read the article

  • What is a Delphi version of the C++ header for the DVP7010B video card DLL?

    - by grzegorz1
    I need help with converting c++ header file to delphi. I spent several days on this problem without success. Below is the original header file and my Delphi translation. C++ header #if _MSC_VER > 1000 #pragma once #endif // _MSC_VER > 1000 #ifdef DVP7010BDLL_EXPORTS #define DVP7010BDLL_API __declspec(dllexport) #else #define DVP7010BDLL_API __declspec(dllimport) #endif #define MAXBOARDS 4 #define MAXDEVS 4 #define ID_NEW_FRAME 37810 #define ID_MUX0_NEW_FRAME 37800 #define ID_MUX1_NEW_FRAME 37801 #define ID_MUX2_NEW_FRAME 37802 #define ID_MUX3_NEW_FRAME 37803 typedef enum { SUCCEEDED = 1, FAILED = 0, SDKINITFAILED = -1, PARAMERROR = -2, NODEVICES = -3, NOSAMPLE = -4, DEVICENUMERROR = -5, INPUTERROR = -6, // VERIFYHWERROR = -7 } Res; typedef enum tagAnalogVideoFormat { Video_None = 0x00000000, Video_NTSC_M = 0x00000001, Video_NTSC_M_J = 0x00000002, Video_PAL_B = 0x00000010, Video_PAL_M = 0x00000200, Video_PAL_N = 0x00000400, Video_SECAM_B = 0x00001000 } AnalogVideoFormat; typedef enum { SIZEFULLPAL=0, SIZED1, SIZEVGA, SIZEQVGA, SIZESUBQVGA } VideoSize; typedef enum { STOPPED = 1, RUNNING = 2, UNINITIALIZED = -1, UNKNOWNSTATE = -2 } CapState; class IDVP7010BDLL { public: int AdvDVP_CreateSDKInstence(void **pp); virtual int AdvDVP_InitSDK() PURE; virtual int AdvDVP_CloseSDK() PURE; virtual int AdvDVP_GetNoOfDevices(int *pNoOfDevs) PURE; virtual int AdvDVP_Start(int nDevNum, int SwitchingChans, HWND Main, HWND hwndPreview) PURE; virtual int AdvDVP_Stop(int nDevNum) PURE; virtual int AdvDVP_GetCapState(int nDevNum) PURE; virtual int AdvDVP_IsVideoPresent(int nDevNum, BOOL* VPresent) PURE; virtual int AdvDVP_GetCurFrameBuffer(int nDevNum, int VMux, long* bufSize, BYTE* buf) PURE; virtual int AdvDVP_SetNewFrameCallback(int nDevNum, int callback) PURE; virtual int AdvDVP_GetVideoFormat(int nDevNum, AnalogVideoFormat* vFormat) PURE; virtual int AdvDVP_SetVideoFormat(int nDevNum, AnalogVideoFormat vFormat) PURE; virtual int AdvDVP_GetFrameRate(int nDevNum, int *nFrameRate) PURE; virtual int AdvDVP_SetFrameRate(int nDevNum, int SwitchingChans, int nFrameRate) PURE; virtual int AdvDVP_GetResolution(int nDevNum, VideoSize *Size) PURE; virtual int AdvDVP_SetResolution(int nDevNum, VideoSize Size) PURE; virtual int AdvDVP_GetVideoInput(int nDevNum, int* input) PURE; virtual int AdvDVP_SetVideoInput(int nDevNum, int input) PURE; virtual int AdvDVP_GetBrightness(int nDevNum, int input, long *pnValue) PURE; virtual int AdvDVP_SetBrightness(int nDevNum, int input, long nValue) PURE; virtual int AdvDVP_GetContrast(int nDevNum, int input, long *pnValue) PURE; virtual int AdvDVP_SetContrast(int nDevNum, int input, long nValue) PURE; virtual int AdvDVP_GetHue(int nDevNum, int input, long *pnValue) PURE; virtual int AdvDVP_SetHue(int nDevNum, int input, long nValue) PURE; virtual int AdvDVP_GetSaturation(int nDevNum, int input, long *pnValue) PURE; virtual int AdvDVP_SetSaturation(int nDevNum, int input, long nValue) PURE; virtual int AdvDVP_GPIOGetData(int nDevNum, int DINum, BOOL* value) PURE; virtual int AdvDVP_GPIOSetData(int nDevNum, int DONum, BOOL value) PURE; }; Delphi unit IDVP7010BDLL_h; interface uses Windows, Messages, SysUtils, Classes; //{$if _MSC_VER > 1000} //pragma once //{$endif} // _MSC_VER > 1000 {$ifdef DVP7010BDLL_EXPORTS} //const DVP7010BDLL_API = __declspec(dllexport); {$else} //const DVP7010BDLL_API = __declspec(dllimport); {$endif} const MAXDEVS = 4; MAXMUXS = 4; ID_NEW_FRAME = 37810; ID_MUX0_NEW_FRAME = 37800; ID_MUX1_NEW_FRAME = 37801; ID_MUX2_NEW_FRAME = 37802; ID_MUX3_NEW_FRAME = 37803; // TRec SUCCEEDED = 1; FAILED = 0; SDKINITFAILED = -1; PARAMERROR = -2; NODEVICES = -3; NOSAMPLE = -4; DEVICENUMERROR = -5; INPUTERROR = -6; // TRec // TAnalogVideoFormat Video_None = $00000000; Video_NTSC_M = $00000001; Video_NTSC_M_J = $00000002; Video_PAL_B = $00000010; Video_PAL_M = $00000200; Video_PAL_N = $00000400; Video_SECAM_B = $00001000; // TAnalogVideoFormat // TCapState STOPPED = 1; RUNNING = 2; UNINITIALIZED = -1; UNKNOWNSTATE = -2; // TCapState type TCapState = Longint; TRes = Longint; TtagAnalogVideoFormat = DWORD; TAnalogVideoFormat = TtagAnalogVideoFormat; PAnalogVideoFormat = ^TAnalogVideoFormat; TVideoSize = ( SIZEFULLPAL, SIZED1, SIZEVGA, SIZEQVGA, SIZESUBQVGA); PVideoSize = ^TVideoSize; P_Pointer = ^Pointer; TIDVP7010BDLL = class function AdvDVP_CreateSDKInstence(pp: P_Pointer): integer; virtual; stdcall; abstract; function AdvDVP_InitSDK():Integer; virtual; stdcall; abstract; function AdvDVP_CloseSDK():Integer; virtual; stdcall; abstract; function AdvDVP_GetNoOfDevices(pNoOfDevs : PInteger) :Integer; virtual; stdcall; abstract; function AdvDVP_Start(nDevNum : Integer; SwitchingChans : Integer; Main : HWND; hwndPreview: HWND ) :Integer; virtual; stdcall; abstract; function AdvDVP_Stop(nDevNum : Integer ):Integer; virtual; stdcall; abstract; function AdvDVP_GetCapState(nDevNum : Integer ):Integer; virtual; stdcall; abstract; function AdvDVP_IsVideoPresent(nDevNum : Integer; VPresent : PBool) :Integer; virtual; stdcall; abstract; function AdvDVP_GetCurFrameBuffer(nDevNum : Integer; VMux : Integer; bufSize : PLongInt; buf : PByte) :Integer; virtual; stdcall; abstract; function AdvDVP_SetNewFrameCallback(nDevNum : Integer; callback : Integer ) :Integer; virtual; stdcall; abstract; function AdvDVP_GetVideoFormat(nDevNum : Integer; vFormat : PAnalogVideoFormat) :Integer; virtual; stdcall; abstract; function AdvDVP_SetVideoFormat(nDevNum : Integer; vFormat : TAnalogVideoFormat ) :Integer; virtual; stdcall; abstract; function AdvDVP_GetFrameRate(nDevNum : Integer; nFrameRate : Integer) :Integer; virtual; stdcall; abstract; function AdvDVP_SetFrameRate(nDevNum : Integer; SwitchingChans : Integer; nFrameRate : Integer) :Integer; virtual; stdcall; abstract; function AdvDVP_GetResolution(nDevNum : Integer; Size : PVideoSize) :Integer; virtual; stdcall; abstract; function AdvDVP_SetResolution(nDevNum : Integer; Size : TVideoSize ) :Integer; virtual; stdcall; abstract; function AdvDVP_GetVideoInput(nDevNum : Integer; input : PInteger) :Integer; virtual; stdcall; abstract; function AdvDVP_SetVideoInput(nDevNum : Integer; input : Integer) :Integer; virtual; stdcall; abstract; function AdvDVP_GetBrightness(nDevNum : Integer; input: Integer; pnValue : PLongInt) :Integer; virtual; stdcall; abstract; function AdvDVP_SetBrightness(nDevNum : Integer; input: Integer; nValue : LongInt) :Integer; virtual; stdcall; abstract; function AdvDVP_GetContrast(nDevNum : Integer; input: Integer; pnValue : PLongInt) :Integer; virtual; stdcall; abstract; function AdvDVP_SetContrast(nDevNum : Integer; input: Integer; nValue : LongInt) :Integer; virtual; stdcall; abstract; function AdvDVP_GetHue(nDevNum : Integer; input: Integer; pnValue : PLongInt) :Integer; virtual; stdcall; abstract; function AdvDVP_SetHue(nDevNum : Integer; input: Integer; nValue : LongInt) :Integer; virtual; stdcall; abstract; function AdvDVP_GetSaturation(nDevNum : Integer; input: Integer; pnValue : PLongInt) :Integer; virtual; stdcall; abstract; function AdvDVP_SetSaturation(nDevNum : Integer; input: Integer; nValue : LongInt) :Integer; virtual; stdcall; abstract; function AdvDVP_GPIOGetData(nDevNum : Integer; DINum:Integer; value : PBool) :Integer; virtual; stdcall; abstract; function AdvDVP_GPIOSetData(nDevNum : Integer; DONum:Integer; value : Boolean) :Integer; virtual; stdcall; abstract; end; function IDVP7010BDLL : TIDVP7010BDLL ; stdcall; implementation function IDVP7010BDLL; external 'DVP7010B.dll'; end.

    Read the article

  • Delphi 5: Ideas for simulating "Obsolete" or "Deprecated" methods?

    - by Ian Boyd
    i want to mark a method as obsolete, but Delphi 5 doesn't have such a feature. For the sake of an example, here is a made-up method with it's deprecated and new preferred form: procedure TStormPeaksQuest.BlowHodirsHorn; overload; //obsolete procedure TStormPeaksQuest.BlowHodirsHorn(UseProtection: Boolean); overload; Note: For this hypothetical example, we assume that using the parameterless version is just plain bad. There are problems with not "using protection" - which have no good solution. Nobody likes having to use protection, but nobody wants to not use protection. So we make the caller decide if they want to use protection or not when blowing Hodir's horn. If we default the parameterless version to continue not using protection: procedure TStormPeaksQuest.BlowHodirsHorn; begin BlowHodirsHorn(False); //No protection. Bad! end; then the developer is at risk of all kinds of nasty stuff. If we force the parameterless version to use protection: procedure TStormPeaksQuest.BlowHodirsHorn; begin BlowHodirsHorn(True); //Use protection; crash if there isn't any end; then there's a potential for problems if the developer didn't get any protection, or doesn't own any. Now i could rename the obsolete method: procedure TStormPeaksQuest.BlowHodirsHorn_Deprecatedd; overload; //obsolete procedure TStormPeaksQuest.BlowHodirsHorn(UseProtection: Boolean); overload; But that will cause a compile error, and people will bitch at me (and i really don't want to hear their whining). i want them to get a nag, rather than an actual error. i thought about adding an assertion: procedure TStormPeaksQuest.BlowHodirsHorn; //obsolete begin Assert(false, 'TStormPeaksQuest.BlowHodirsHorn is deprecated. Use BlowHodirsHorn(Boolean)'); ... end; But i cannot guarantee that the developer won't ship a version without assertions, causing a nasty crash for the customer. i thought about using only throwing an assertion if the developer is debugging: procedure TStormPeaksQuest.BlowHodirsHorn; //obsolete begin if DebugHook > 0 then Assert(false, 'TStormPeaksQuest.BlowHodirsHorn is deprecated. Use BlowHodirsHorn(Boolean)'); ... end; But i really don't want to be causing a crash at all. i thought of showing a MessageDlg if they're in the debugger (which is a technique i've done in the past): procedure TStormPeaksQuest.BlowHodirsHorn; //obsolete begin if DebugHook > 0 then MessageDlg('TStormPeaksQuest.BlowHodirsHorn is deprecated. Use BlowHodirsHorn(Boolean)', mtWarning, [mbOk], 0); ... end; but that is still too disruptive. And it has caused problems where the code is stuck at showing a modal dialog, but the dialog box wasn't obviously visible. i was hoping for some sort of warning message that will sit there nagging them - until they gouge their eyes out and finally change their code. i thought perhaps if i added an unused variable: procedure TStormPeaksQuest.BlowHodirsHorn; //obsolete var ThisMethodIsObsolete: Boolean; begin ... end; i was hoping this would cause a hint only if someone referenced the code. But Delphi shows a hint even if you don't call actually use the obsolete method. Can anyone think of anything else?

    Read the article

  • Programmatically change the default code page in Windows XP? (from Delphi)

    - by Duncan
    Could anyone advise how to programmatically change the default Windows XP code page (I'm doing this from Delphi)? (This would be the equivalent of going into Control Panel - Regional Settings - Language for non-Unicode applications). In this case, I want to switch to Chinese (PRC) and so am writing to the following registry strings: HKLM\SYSTEM\CurrentControlSet\Control\Nls\CodePage\ ACP=936 MACCP=10008 OEMCP=936 (Which is exactly what changing the non-Unicode codepage drop down in Control Panel does). There must be another setting which I need to change - and I'd prefer to use a Win API call (if available) rather than writing to the registry myself. I've also tried setting HKLM\SYSTEM\CurrentControlSet\Control\Nls\Language\ Default=0804 (Chinese PRC) to no avail. I don't want to change the 'locale' per se as this will also change time / date settings, separators, etc. etc. This is because I'm using an ANSI application that needs to render Chinese characters, and I'm writing a tool to automatically switch the system show the characters (while leaving other aspects of the UI intact). Thanks! Duncan

    Read the article

  • What is the right tool to detect VMT or heap corruption in Delphi ?

    - by Roland Bengtsson
    I'm a member in a team that use Delphi 2007 for a larger application and we suspect heap corruption because sometimes there are strange bugs that have no other explanation. I believe that the Rangechecking option for the compiler is only for arrays. I want a tool that give an exception or log when there is a write on a memory address that is not allocated by the application. Regards EDIT: The error is of type: Error: Access violation at address 00404E78 in module 'BoatLogisticsAMCAttracsServer.exe'. Read of address FFFFFFDD EDIT2: Thanks for all suggestions. Unfortunately I think that the solution is deeper than that. We use a patched version of Bold for Delphi as we own the source. Probably there are some errors introduced in the Bold framwork. Yes we have a log with callstacks that are handled by JCL and also trace messages. So a callstack with the exception can lock like this: 20091210 16:02:29 (2356) [EXCEPTION] Raised EBold: Failed to derive ServerSession.mayDropSession: Boolean OCL expression: not active and not idle and timeout and (ApplicationKernel.allinstances->first.CurrentSession <> self) Error: Access violation at address 00404E78 in module 'BoatLogisticsAMCAttracsServer.exe'. Read of address FFFFFFDD. At Location BoldSystem.TBoldMember.CalculateDerivedMemberWithExpression (BoldSystem.pas:4016) Inner Exception Raised EBold: Failed to derive ServerSession.mayDropSession: Boolean OCL expression: not active and not idle and timeout and (ApplicationKernel.allinstances->first.CurrentSession <> self) Error: Access violation at address 00404E78 in module 'BoatLogisticsAMCAttracsServer.exe'. Read of address FFFFFFDD. At Location BoldSystem.TBoldMember.CalculateDerivedMemberWithExpression (BoldSystem.pas:4016) Inner Exception Call Stack: [00] System.TObject.InheritsFrom (sys\system.pas:9237) Call Stack: [00] BoldSystem.TBoldMember.CalculateDerivedMemberWithExpression (BoldSystem.pas:4016) [01] BoldSystem.TBoldMember.DeriveMember (BoldSystem.pas:3846) [02] BoldSystem.TBoldMemberDeriver.DoDeriveAndSubscribe (BoldSystem.pas:7491) [03] BoldDeriver.TBoldAbstractDeriver.DeriveAndSubscribe (BoldDeriver.pas:180) [04] BoldDeriver.TBoldAbstractDeriver.SetDeriverState (BoldDeriver.pas:262) [05] BoldDeriver.TBoldAbstractDeriver.Derive (BoldDeriver.pas:117) [06] BoldDeriver.TBoldAbstractDeriver.EnsureCurrent (BoldDeriver.pas:196) [07] BoldSystem.TBoldMember.EnsureContentsCurrent (BoldSystem.pas:4245) [08] BoldSystem.TBoldAttribute.EnsureNotNull (BoldSystem.pas:4813) [09] BoldAttributes.TBABoolean.GetAsBoolean (BoldAttributes.pas:3069) [10] BusinessClasses.TLogonSession._GetMayDropSession (code\BusinessClasses.pas:31854) [11] DMAttracsTimers.TAttracsTimerDataModule.RemoveDanglingLogonSessions (code\DMAttracsTimers.pas:237) [12] DMAttracsTimers.TAttracsTimerDataModule.UpdateServerTimeOnTimerTrig (code\DMAttracsTimers.pas:482) [13] DMAttracsTimers.TAttracsTimerDataModule.TimerKernelWork (code\DMAttracsTimers.pas:551) [14] DMAttracsTimers.TAttracsTimerDataModule.AttracsTimerTimer (code\DMAttracsTimers.pas:600) [15] ExtCtrls.TTimer.Timer (ExtCtrls.pas:2281) [16] Classes.StdWndProc (common\Classes.pas:11583) The inner exception part is the callstack at the moment an exception is reraised. EDIT3: The theory right now is that the Virtual Memory Table (VMT) is somehow broken. When this happen there is no indication of it. Only when a method is called an exception is raised (ALWAYS on address FFFFFFDD, -35 decimal) but then it is too late. You don't know the real cause for the error. Any hint of how to catch a bug like this is really appreciated!!! We have tried with SafeMM, but the problem is that the memory consumption is too high even when the 3 GB flag is used. So now I try to give a bounty to the SO community :) EDIT4: One hint is that according the log there is often (or even always) another exception before this. It can be for example optimistic locking in the database. We have tried to raise exceptions by force but in test environment it just works fine. EDIT5: Story continues... I did a search on the logs for the last 30 days now. The result: "Read of address FFFFFFDB" 0 "Read of address FFFFFFDC" 24 "Read of address FFFFFFDD" 270 "Read of address FFFFFFDE" 22 "Read of address FFFFFFDF" 7 "Read of address FFFFFFE0" 20 "Read of address FFFFFFE1" 0 So the current theory is that an enum (there is a lots in Bold) overwrite a pointer. I got 5 hits with different address above. It could mean that the enum holds 5 values where the second one is most used. If there is an exception a rollback should occur for the database and Boldobjects should be destroyed. Maybe there is a chance that not everything is destroyed and a enum still can write to an address location. If this is true maybe it is possible to search the code by a regexpr for an enum with 5 values ? EDIT6: To summarize, no there is no solution to the problem yet. I realize that I may mislead you a bit with the callstack. Yes there are a timer in that but there are other callstacks without a timer. Sorry for that. But there are 2 common factors. An exception with Read of address FFFFFFxx. Top of callstack is System.TObject.InheritsFrom (sys\system.pas:9237) This convince me that VilleK best describe the problem. I'm also convinced that the problem is somewhere in the Bold framework. But the BIG question is, how can problems like this be solved ? It is not enough to have an Assert like VilleK suggest as the damage has already happened and the callstack is gone at that moment. So to describe my view of what may cause the error: Somewhere a pointer is assigned a bad value 1, but it can be also 0, 2, 3 etc. An object is assigned to that pointer. There is method call in the objects baseclass. This cause method TObject.InheritsForm to be called and an exception appear on address FFFFFFDD. Those 3 events can be together in the code but they may also be used much later. I think this is true for the last method call. EDIT7: We work closely with the the author of Bold Jan Norden and he recently found a bug in the OCL-evaluator in Bold framework. When this was fixed these kinds of exceptions decreased a lot but they still occasionally come. But it is a big relief that this is almost solved.

    Read the article

  • Delphi 10, .NET, how do I convert a hex UTF-8 string to its unicode character?

    - by Evan V.
    Hi all, I am trying to make my web app compatible with international languages and I am stuck with trying to convert escaped characters in my Delphi .NET DLL. The front end code is passing the UTF-8 hex notation with an escape character e.g for ? I pass \uE3818A. In my DLL I capture this and constract the following string '$E3828A'. I need to convert this back to ? and send it to my database, I've been trying to use Encoding.UTF8.GetBytes and Encoding.UTF8.GetString but with no luck. Anyone could help me figure this out? Thank you.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 95 96 97 98 99 100 101 102 103 104 105 106  | Next Page >