BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  pointer assignment not happening..          BorlandTalk.com Forum Index -> C++ Builder (Language C++) View previous topic :: View next topic   Author Message Jeff Kish Guest Posted: Fri Jul 28, 2006 9:00 pm    Post subject: pointer assignment not happening.. HI. I have a dll with this method in it: long getFormImageFromId(long lId, TFormImage * pForm) { for (vFormImageId_Iter iter = vFormImageIds.begin(); iter != vFormImageIds.end(); iter++) { FormImageId pImage = *iter; if ((pImage.pForm != NULL) && (pImage.lId == lId)) // && (::IsWindow(pImage.pForm->Handle) != 0)) { pForm = pImage.pForm; //this gets executed with a proper //value assigned to pForm. return myResultOK; } return myResultBAD; } I call it like this from inside another method in the dll: TFormImage *pForm = NULL; long lResult = getFormImageFromId(lId, pForm); after the call, pForm is NULL, even though the pointer got assigned inside the getFormImageFromId call. shouldn't it of been assigned? I must be exhausted to miss the obvious? Thanks Jeff Kish Back to top Clayton Arends Guest Posted: Fri Jul 28, 2006 9:20 pm    Post subject: Re: pointer assignment not happening.. When pForm is set in the function the local pointer is changed and not the caller. If you want to change the caller then the declaration of your function needs to change. You either need a pointer to a pointer or a reference to a pointer: long getFormImageFromId(long lId, TFormImage ** pForm) long getFormImageFromId(long lId, TFormImage *& pForm) If you use the second one then you won't have to make any other changes to your code. If you use the first one then you will have to dereference the pointer in the function (*pForm = pImage.pForm) and change the call to the function to pass a pointer to a pointer (&pForm). HTH, - Clayton Back to top Ed Mulroy Guest Posted: Fri Jul 28, 2006 9:20 pm    Post subject: Re: pointer assignment not happening.. Quote: long getFormImageFromId(long lId, TFormImage * pForm) : pForm = pImage.pForm; //this gets executed ... : after the call, pForm is NULL... Shouldn't that be: *pForm = pImage.pForm; instead of pForm = pImage.pForm; Welcome to the 2+2=5 club. I've visited it many times. .. Ed Quote: Jeff Kish wrote in message news:vsckc2lqd124eacted88lk1l2o1hbopdfl (AT) 4ax (DOT) com... I have a dll with this method in it: long getFormImageFromId(long lId, TFormImage * pForm) { for (vFormImageId_Iter iter = vFormImageIds.begin(); iter != vFormImageIds.end(); iter++) { FormImageId pImage = *iter; if ((pImage.pForm != NULL) && (pImage.lId == lId)) // && (::IsWindow(pImage.pForm->Handle) != 0)) { pForm = pImage.pForm; //this gets executed with a proper //value assigned to pForm. return myResultOK; } return myResultBAD; } I call it like this from inside another method in the dll: TFormImage *pForm = NULL; long lResult = getFormImageFromId(lId, pForm); after the call, pForm is NULL, even though the pointer got assigned inside the getFormImageFromId call. shouldn't it of been assigned? I must be exhausted to miss the obvious? Back to top Jeff Kish Guest Posted: Fri Jul 28, 2006 9:42 pm    Post subject: Re: pointer assignment not happening.. On Fri, 28 Jul 2006 09:20:01 -0700, "Clayton Arends" <nospam_claytonarends (AT) hotmail (DOT) com> wrote: Quote: When pForm is set in the function the local pointer is changed and not the caller. If you want to change the caller then the declaration of your function needs to change. You either need a pointer to a pointer or a reference to a pointer: long getFormImageFromId(long lId, TFormImage ** pForm) long getFormImageFromId(long lId, TFormImage *& pForm) If you use the second one then you won't have to make any other changes to your code. If you use the first one then you will have to dereference the pointer in the function (*pForm = pImage.pForm) and change the call to the function to pass a pointer to a pointer (&pForm). HTH, - Clayton Thanks, yes it does. Quote: Shouldn't that be: *pForm = pImage.pForm; instead of pForm = pImage.pForm; Welcome to the 2+2=5 club. I've visited it many times. . Ed getting old is entirely overrated. Thanks I guess I should of remembered I could change things dereferenced by the pointer, but not the pointer value itself.... sigh. Jeff Kish Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         BorlandTalk.com Forum Index -> C++ Builder (Language C++) All times are GMT Page 1 of 1   Jump to: Select a forum C++ Builder Newsgroups----------------C++ BuilderC++ Builder (ActiveX)C++ Builder (Announcements)C++ Builder (Command Line Tools)C++ Builder DatabasesC++ Builder Databases (ADO)C++ Builder Databases (Desktop)C++ Builder Databases (InterBase Express)C++ Builder Databases (Multi-Tier)C++ Builder Databases (SQL Servers)C++ Builder (Graphics)C++ Builder (IDE)C++ Builder (Internet)C++ Builder (Internet Socket)C++ Builder (Internet Web)C++ Builder (Jobs)C++ Builder (Language)C++ Builder (Language C++)C++ Builder (Compatibility with MFC)C++ Builder (Native API)C++ Builder (Non-Technical)C++ Builder (Students)C++ Builder (Third Party Tools)C++ Builder (Upgrade)C++ Builder (VCL)C++ Builder (VCL Components Usage)C++ Builder (VCL Components Development)C++ Builder (VCL Usage)C++ Builder (WinAPI)C++ Builder Installation Delphi Newsgroups----------------Delphi (General)Delphi ActiveX Controls UsageDelphi ActiveX Controls DevelopmentDelphi As400Delphi DatabasesDelphi Databases (ADO)Delphi Databases (dbExpress)Delphi Databases (Desktop)Delphi Databases (InterBase Express)Delphi Databases (Multi-Tier)Delphi Databases (SQL Servers)Delphi DeploymentDelphi GraphicsDelphi IDEDelphi InternationalizationDelphi InternetDelphi Internet Isapi-WebBrokerDelphi Internet WebSnapDelphi Internet WinsockDelphi JobsDelphi Language BASMDelphi Language ObjectPascalDelphi Model Driven Architecture (General)Delphi Model Driven Architecture (Third Party)Delphi MultimediaDelphi Native APIDelphi Non-TechnicalDelphi ObjectPascalDelphi OLE AutomationDelphi OO designDelphi OpenToolsAPIDelphi Reporting-ChartingDelphi RTLDelphi StudentsDelphi TeamSourceDelphi Thirdparty ToolsDelphi Thirdparty Tools (General)Delphi Thirdparty Tools (IntraWeb)Delphi Thirdparty Tools (RaveReports)Delphi UpgradeDelphi VCLDelphi VCL ComponentsDelphi VCL Components UsingDelphi VCL Components WritingDelphi WebServices SOAPDelphi WinAPIDelphi XMLDelphi Installationcomp.lang.pascal.delphi.components.misccomp.lang.pascal.delphi.components.usagecomp.lang.pascal.delphi.components.writingcomp.lang.pascal.delphi.databasescomp.lang.pascal.delphi.misccomp.sources.delphi JBuilder Newsgroups----------------JBuilderJBuilder AnnouncementsJBuilder Applet IssuesJBuilder As400JBuilder CompilerJBuilder CORBA/RMIJBuilder DatabasesJBuilder DB SwingJBuilder DebuggerJBuilder DeploymentJBuilder DocumentationJBuilder EnterpriseJBuilder HandheldJBuilder IDEJBuilder JavaJBuilder JavaAPIJBuilder Java LanguageJBuilder Java SwingJBuilder Java BeansJBuilder Java Beans UsageJBuilder Java Beans DevelopmentJBuilder JBCLJBuilder JDataStoreJBuilder JobsJBuilder LinuxJBuilder MacintoshJBuilder & MobileSetJBuilder MultiLingual AppsJBuilder Non-TechnicalJBuilder OpenToolsJBuilder Servlets (JSP)JBuilder StudentsJBuilder Team DevelopmentJBuilder Thirdparty ToolsJBuilder UpgradeJBuilder Installation InterBase Newsgroups----------------InterBaseInterBase Bug DiscussionInterBase GeneralInterBase IBConsoleInterBase OpenSourceInterBase ReplicationInterBase SQLInterBase ThirdpartyInterBase Installation Miscellaneous Borland Newsgroups----------------AppCenterAppServerEnteraVisiBroker  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.