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From: JG on 24 Oct 2007 05:18 Another novice question, exception occurring at depicted location of code below, appreciate all comments: //Before calling EnumDisplaySettings, set the dmSize member to sizeof(DEVMODE), //and set the dmDriverExtra member to indicate the size, in bytes, of the additional //space available to receive private driver-data. DWORD iModeNum = 0; // specifies the graphics mode LPDEVMODE lpSavCurDevMode; // saving current mode struct //Here I'm tring to assign the value of dmSize to sizeof(DEVMODEW) but there is a problem lpSavCurDevMode->dmSize = sizeof(DEVMODEW); <-------------this pulls an exception lpSavCurDevMode->dmDriverExtra = 64; LPDEVMODE lpDevMode[10]; //other mode data recieving structs BOOL EnumRET; //Save the Current Device Mode settings, // EnumRET = EnumDisplaySettings(NULL, ENUM_CURRENT_SETTINGS, lpSavCurDevMode); for (iModeNum = 0; iModeNum <=10; iModeNum = iModeNum + 1) { EnumRET = EnumDisplaySettings(NULL, iModeNum, lpDevMode[iModeNum]); if (EnumRET==0) break; lpDevMode[iModeNum]->dmSize = sizeof(DEVMODEW); lpDevMode[iModeNum]->dmDriverExtra = 64; }
From: Gianni Mariani on 24 Oct 2007 05:23 JG wrote: > Another novice question, exception occurring at depicted location of code below, > appreciate all comments: > > //Before calling EnumDisplaySettings, set the dmSize member to sizeof(DEVMODE), > //and set the dmDriverExtra member to indicate the size, in bytes, of the additional > //space available to receive private driver-data. > DWORD iModeNum = 0; // specifies the graphics mode > LPDEVMODE lpSavCurDevMode; // saving current mode struct > > //Here I'm tring to assign the value of dmSize to sizeof(DEVMODEW) but there is a problem > lpSavCurDevMode->dmSize = sizeof(DEVMODEW); <-------------this pulls an exception lpSavCurDevMode seems to be uninitialized. What should be in there ?
From: Daniel T. on 24 Oct 2007 06:47 In article <ffn2m902ik8(a)news4.newsguy.com>, "JG" <NoMail(a)NoSpam> wrote: > Another novice question, exception occurring at depicted location of code > below, > appreciate all comments: > > //Before calling EnumDisplaySettings, set the dmSize member to > sizeof(DEVMODE), > //and set the dmDriverExtra member to indicate the size, in bytes, of the > additional > //space available to receive private driver-data. > DWORD iModeNum = 0; // specifies the graphics mode > LPDEVMODE lpSavCurDevMode; // saving current mode struct > > //Here I'm tring to assign the value of dmSize to sizeof(DEVMODEW) but there > is a problem > lpSavCurDevMode->dmSize = sizeof(DEVMODEW); <-------------this pulls an > exception lpSavCurDevMode points to an invalid place in memory. You have to initialize it first.
From: JG on 24 Oct 2007 19:41 "Daniel T."> > lpSavCurDevMode points to an invalid place in memory. >You have to initialize it first. ----------------------- Thanks for the reply but is there an easier way to do this than actually pasting in the entire structure (shown below) and assigning each variable type a value?? Additionally how would I intialize an array of structures, this could get quite involved could it not? typedef struct _devicemodeA { BYTE dmDeviceName[CCHDEVICENAME]; WORD dmSpecVersion; WORD dmDriverVersion; WORD dmSize; WORD dmDriverExtra; DWORD dmFields; union { struct { short dmOrientation; short dmPaperSize; short dmPaperLength; short dmPaperWidth; }; POINTL dmPosition; }; short dmScale; short dmCopies; short dmDefaultSource; short dmPrintQuality; short dmColor; short dmDuplex; short dmYResolution; short dmTTOption; short dmCollate; BYTE dmFormName[CCHFORMNAME]; WORD dmLogPixels; DWORD dmBitsPerPel; DWORD dmPelsWidth; DWORD dmPelsHeight; DWORD dmDisplayFlags; DWORD dmDisplayFrequency; #if(WINVER >= 0x0400) DWORD dmICMMethod; DWORD dmICMIntent; DWORD dmMediaType; DWORD dmDitherType; DWORD dmReserved1; DWORD dmReserved2; #if (WINVER >= 0x0500) || (_WIN32_WINNT >= 0x0400) DWORD dmPanningWidth; DWORD dmPanningHeight; #endif #endif /* WINVER >= 0x0400 */
From: Daniel T. on 24 Oct 2007 23:36
"JG" <NoMail(a)NoSpam> wrote: > ...is there an easier way to do this than actually pasting in the > entire structure (shown below) and assigning each variable type a > value? Every variable in a program has to have a valid value before it can be used constructivly. Some value that is useful in the context of that variable. What you ask is like asking if you can build a car without bothering to make sure that the nuts fit the bolts. > Additionally how would I intialize an array of structures, this > could get quite involved could it not? Generally, arrays are created because they all, in some sense, can be treated the same. So write loops that go through each of the variables in the array and assign them a useful value. |