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A dos pointer (as you put it) is just a standard C string pointer (char*) and these are passed to DLLs all the time.
The question are:
What is the DLL doing with the string?
Are you telling the DLL how much space it has to work with?
Are you sure the DLL is not over-running the buffer?
Are you passing a static or const string?
Is the DLL written using C or C++?
You could pass the string along with a seperate buffer (+size of buffer) to store the resulting string in, but that should not be needed.
In general calling a function/method in DLL is just like calling a function in your own code or one of the standard C/C++ libraries.
Trust in the code Luke. Yea right!
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The DLL Should be just concatenating it with another string.
No im not telling the DLL how much space it has to work with.
shouldnt be overrunning the buffer.
static or const dunno the base app cannot pass strings as such just
a dosptr using somet like dll_call whichdll stack "P" var.
C++
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Depends on what type of program is calling the dll function. You typically cannot realloc the string, nor change the length of the string if calling from VB.
onwards and upwards...
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Hi!
I’ve noted that some wave editor programs (e.g. Wavelab 4.0) displays wave files in a very attractive fashion. Instead of plotting the xy values (time vs intensity) by simply connecting each two consecutive points with straight lines, they draw the envelope of the wave (upper and lower parts) and then fills the inner part.
Any idea about the algorithm they are using to produce such a nice plots?
Thanks,
Carlos
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I have a derived CRichEditCtrl making use of the rich edit DLL RICHED20.DLL in a Dialog based application as a custom control and am trying to implement the "Select All" functionality found in the standard Edit menu of most applications. I tried using SetSel(0,-1) to select all the text in the RichEdit Control but it doesn't appear to work. Maybe I am going about this the wrong way, my desired behavior would be to have all of the text highlighted. How would I go about doing this based on my situation?
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I am trying to create a pointer to a struct, but I keep getting errors.
I have been converting a *.c file to c++ and I am not too familuar with C.
I need to know the size of each one so I know what offset in memory to access the data.
i.e. if the header is 16 bytes long then I know anything larger than 16 bytes is the data values that I need.
I want to be able to access
SimSignal->Min[i];
SimSignal->Max[i];
SimSignal->Value[i];
SimSignal->Name[i];
SimSignal->Unit[i];
All of this data is related to one another.
I hope this makes sense.
Thanks for the help,
Steven
<br />
#define SIMHEAD_ADR 0x40 //This is the hardcoded address of the SimHeader (only hard coded address to RFM)<br />
<br />
<br />
struct TSimHeader<br />
{<br />
int SimWriteFlag; <br />
int DisplayReadFlag; <br />
int SignalCount; <br />
int SimStatus;<br />
};<br />
<br />
<br />
struct TSimSignal<br />
{<br />
double Min[88];
double Max[88];
double Value[88];
char Name[88];
char Unit[88];
};<br />
<br />
<br />
<br />
<br />
TSimHeader* SimHeader= SIMHEAD_ADR;<br />
TSimSignal* SimSignal= SimHeader+sizeof(TSimHeader);<br />
<br />
<br />
d:\.....h(42) : error C2258: illegal pure syntax, must be '= 0'
d:\.....h(42) : error C2252: 'SimHeader' : pure specifier can only be specified for functions
d:\.....h(43) : error C2065: 'SimHeader' : undeclared identifier
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You left off a } somewhere. The compiler thinks it's still in a struct definition when it sees SimHeader = SIMHEAD_ADR and thinks you're declaring a pure-virtual function.
--Mike--
"So where does that leave us? Well, it leaves us right back where we started, only more confused than before." -- Matt Gullett
Ericahist | Homepage | RightClick-Encrypt | 1ClickPicGrabber
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Actually, you need to prefix the type specifier with the keyword struct.
ex:
struct TSimHeader* SimHeader= SIMHEAD_ADR;
struct TSimSignal* SimSignal= SimHeader+sizeof(TSimHeader);
onwards and upwards...
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Michael Dunn is probubly right about the error messages you received.
But you seem to have a few other problems:
TSimHeader* SimHeader= (TSimHeader*)SIMHEAD_ADR;
TSimSignal* SimSignal= (TSimSignal*)(SimHeader+1);
// This last is equivalent to
TSimSignal* SimSignal= (TSimSignal*)((char*)SimHeader+sizeof(TSimHeader));
//or
TSimSignal* SimSignal= (TSimSignal*)(SimHeader[1]); // Bad, but should work
Trust in the code Luke. Yea right!
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Does anyone know how to install the resource editor. It does not show up in the Add-in manager. It has a batch file and when I click it it seems to install, but I can't use that editor.
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I get the following errors when I declare this struct.
<br />
struct SimSignal<br />
{<br />
double Min;
double Max;
double Value;
char[88] Name;
char[16] Unit;
};<br />
<br />
d:\........h(17) : error C2059: syntax error : '['
d:\........h(17) : error C2238: unexpected token(s) preceding ';'
Looks right to me.
Any Ideas?
Thanks,
Steven
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thanks,
I have been converting a *.c file to c++.
steven
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I`m sorry but is the same in c and c++;););)
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Hi,
I got a question with MFC. I have a Dialog and a Scroll bar. A child window (of the dialog) is created and is a lot bigger than the dialog. I want to scroll the window. Srolling work fine, but it's not smooth, a bifg rectangle at the bottom or the top (depending if you scroll down or up) is redrawing the window (like an InvalidateRect). Check out the code: (in the mouse whell event):
if (zDelta<0)
{
if (m_nScrollPos < nMaxPos)
{
zDelta = min(max(nMaxPos/20,5),nMaxPos-m_nScrollPos);
m_nRecalibrateMouse += zDelta;
m_nScrollPos += zDelta;
m_pcScrollBar->SetScrollPos(m_nScrollPos,TRUE);
// that when I move the CWnd -->
m_pcMainWindows->SetWindowPos(NULL, 0, -m_nScrollPos, m_pcMainWindows->MyGetm_nWidth(),m_pcMainWindows->MyGetm_nHeigth(),SWP_NOZORDER | SWP_NOACTIVATE);
}
}
else ...
Thank for helping !
Charles
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this is the code i used in eVC++, in the Windows CE API in the WinMain function, from grattan's, [i]pocket pc development in the enterprise.[/i]
SHELLEXECUTEINFO sei;
TCHAR tFile[255];
if (lpCmdLine[0]==0) wsprintf(tFile, TEXT("\\ePowerDiagnostic.vb"));
else
wsprintf(tFile, lpCmdLine);
ZeroMemory(&sei, sizeof(sei));
sei.cbSize = sizeof(sei);
sei.lpFile = tFile;
return ShellExecuteEx(&sei);
return 0;
supposedly, since the eVB application (project1.vb, [i]ePowerDiagnostic.vb in my case[/i])is "associated with the pvbload.exe, the ShellExecuteEx will load the pvbload.exe file with the project1.vb as a parameter ( just as if we were tapping the project1.vb file from the start menu or programs folder.
however, i followed the instruction, imported an icon, and compiled by using the relase suffix and building the project. i copied the lauch app to the device. however, the error msg i keep getting on the pocket pc is
" 'ePowerDiagnostic' is not a valid Pocket PC application "
I'm not sure where I went wrong....
thx.
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If I have two processes with normal priority, and each has a thread running with different priorities like this:
Process 1
|- Thread 1 (High Priority)
Process 2
|- Thread 2 (Normal Priority)
I'm trying to work out whether the high priority on the thread affects only the thread's chances of getting a slice within the context of slices available for the process, or whether it affects the allocation of slices at the same level as process priority.
That's not hugely clear, I know. Given this scenario, will Thread 1 get more time on the processor than Thread 2 (even though the processes have equal priority)?
Any ideas? Thanks.
--
Simon Steele
Programmers Notepad - http://www.pnotepad.org/
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I believe a thread priority is relative to the priority of the process it resides in.
Kuphryn
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The Base Priority of a thread is determined by both the process priority class, and the thread priority. It's just two different mechanisms (one to weight processes in the system, one to weight threads inside one process)
Thread 1 will (almost) always get scheduled first when both are waiting for an event or similar.
The scheduler always schedules the thread of the highest priority that is ready to run. So Thread 1 will starve thread 2, if it doesn't give up processor time or a second CPU is available.
The one exception is: Input goes to Thread 2. When input waits in the queue for a thread, it's priority is temporarily boosted.
"Der Geist des Kriegers ist erwacht / Ich hab die Macht" StS
sighist | Agile Programming | doxygen
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(1)I have an array of pixels to be displayed. Does someone know how to do that?
{
....
char* pixelarray = malloc(sizeof(uint32)*width*height);
fill_in_content(pixelarray);
//how to display the pixelarray on the screen now?
}
(2) if I have an linked list data structure to represent the pixel
struct link_list
{
char pixelvalue[4];
link_list* next;
}link_list;
{
...
link_list* head
build_linked_list(head, width*height);
fill_in_content(head, width*height);
//how to display the content in the linked list to screen?
}
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I'm no GDI expert but a pixel has three properties: X coord, Y coord, and RGB value. With these three values, you can render a pixel at a certain location in the desired color.
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Either create it as a bitmap and use bitblt() or, if you really want to paint each pixel... SetPixel().
onwards and upwards...
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SetPixel() will be slow though.
John
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I created a CStatic subclass that handles ON_WM_KEYDOWN and can capture the key presses ok, but when a key is pressed it generates the beeping sound you usually get when a key press isn't being handled. If anyone knows how I can stop this or where I should start looking I'd appreciate it.
(Also if anyone knows how to capture arrowkey events please let me know, none of ON_WM_KEYDOWN, ON_WM_SYSKEYDOWN, or ON_WM_CHAR seem to catch them)
Thanks
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I'd guess that it's the keyboard device driver intercepting the keystroke before passing it on to Windows.
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