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Call GetLastError() upon failure to know more about the reason.
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Thank you, I had tried to see what GetLastError get me, but get me nothing, I mean 0 ... always 0 ...
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There are situations that GetLastError() returns 0 when the call fails (from MSDN and looking at the source of the MFC function):
- When a bitmap handle is already attached to the
CBitmap (asserts also); - When using Windows 9x (last error is never set, size is limited to 16 MB);
- When this can happen without being documented in the MSDN.
I hope this information helps you to find the reason.
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Hello Everybody,
I am trying to pass some values to char ** (to a third party library). But i am getting some issue in that.
char** ids = new char*[m_Size];
for(int i=0; i<m_Size; i++)
{
ids[i] = mSizes[i].GetBuffer(mSizes[i].GetLength()); }
using that third party function, its creating an output file and in that file the stored value is showing like this.
GROUP : 46,0
GROUP : 44,0
GROUP : 42,0
GROUP : ÝÝÝÝÝÝÝ݆«ãe,0
GROUP : 40,0
GROUP : 38,0
But if I give values like this, then in output file, the values are showing fine.
char* ids[6] = {"38", "40", "42", "44", "46", "48"};
in the output file,
GROUP : 38,0
GROUP : 40,0
GROUP : 42,0
GROUP : 44,0
GROUP : 46,0
GROUP : 48,0
(see the sequence also)
what i am doing wrong? initialization ? or passing values ?
Thanks,
A. Gopinath.
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The code looks fine. Because only one of the strings from your array returns wrong data, this element may be corrupted somewhere else.
Note also that you must call ReleaseBuffer() for each string array element after calling the library function. If not doing so, further accesses may return invalid data.
You should also check the documentation of the library if the passed strings are constant or may be changed. If they may be changed, you must pass the max. allowed length to GetBuffer().
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char** ids = new char*[m_Size];
Here you create an array of char pointers.
Here:
ids[i] =
you need to create an aray of chars, so it should be ids[i] = new char [<some number="">]
Then copy the data into the char array.
==============================
Nothing to say.
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In the first case, the pointers are pointing to memory maintained by the CStringArray class.
It is likely that CStringArray relocated, resized or moved the memory around.
So you need to allocate memory for each pointer and copy the contents to the allocated memory.
In the second case you have pointers to fixed locations that do not change.
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I am aurpsised it even runs with out crashing since he is setting his array pointers to the values contained in some string!
So if the string was 'this monkley is stupid' the first pointer will have the value of the ASCII codes for 'this', the second pointer ' mon' and so on.
Of course these addresses are completely invalid and point to somewhere in his process. If he manipulated them in any way its bye bye process time!
==============================
Nothing to say.
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Hi,I want to change the string of a menu item,the string contains a '\t',like
"hello\tworld",I use CMenu::ModifyMenu function,I tried many times,the string always "hello",not"hello world",It will lost the string after '\t',Why,How to change it.
Thanks
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Show some more of the actual code; there may be something wrong with it.
Use the best guess
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With menu items, the tab character is used to right align text in a new column (commonly to print accelerator short cuts). See also the MENUITEM statement[^] in the MSDN.
So even when its is working, the result may be not the one expected by you.
I don't know why the text right of the tab is not shown by your application. Did you call CWnd::DrawMenuBar() after changing the menu content? If not, this may be the reason.
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I use vs2010,The Menu item got from CMFCMenuBar,like this:
CMenu *pMenu = CMenu::FromHandle(m_wndMenuBar.GetDefaultMenu());
CMenu *pSubMenu = pMenu ->GetSubMenu(1);
Cstring strText = _T("Hello\tworld");
pSubMenu ->ModifyMenu(ID_CHANGE, MF_BYCOMMAND, ID_CHANGE, strText);
I use DrawMenuBar ,it still doesn't work,why
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I don't know why.
You may check if tabs are shown when using in resource based menus. If not, the problem is application based. You may also check if '\a' is working (same as '\t' but text is left aligned).
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Hi,
I create a derived Cdialog with following code
main_window->progdbg = new CprogDebug();
main_window is main windows I get the pointer to it via AfxGetMainWInd
CMainFrame* main_window = (CMainFrame *) AfxGetMainWnd();
CMainFrame is created on the heap
later on when I try to create the the window modeless dialog it never comes back to me the is that is the create
ret = progdbg->Create(IDD_PROGDBG,(CWnd *)this);
if(ret == 0 )
error = GetLastError();
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I use the VC++ 2008 to check this question. I define one function named "max2" using keyword "static" and one function named "min2" using keyword "inline". I think that the compiler will use the code inside the min2 function to replace the function called. And the max2 with static keyword will be compiled to be a function.
But after the Deassembled in Debug model. I found that the exe both use the "call " assemble code to call these two functions. why does the inline not succeed?
modified 14-May-13 10:16am.
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You have the idea right, but there are several issues with inline. Here is a list off the top of my head:
1. You can change the setting in the Project Properties -> C/C++ -> Optimizations -> Inline Function Expansion.
2. You say you de-assembled the Debug build of your exe, but for Debug builds the default setting is Disabled.
3. The inline keyword does not order the compiler to expand the function inline, it is merely a request. The compiler will determine if it is worth making it inline or if it is better left as a function call.
4. If a function is marked as inline and called from multiple other function, it might be inlined in some of the calling functions and not in others. Again the compiler determines whether it is worth it.
5. If you discover that the compiler is not inlining a function you have marked as inline and you really, really, really want it inlined because you think you know better or you want to run profiling with it inlined and not inlined, try using the __forceinline keyword.
http://msdn.microsoft.com/en-us/library/z8y1yy88(v=vs.90).aspx[^]
Soren Madsen
"When you don't know what you're doing it's best to do it quickly" - Jase #DuckDynasty
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A static method can be inlined if the compiler decides to do so, and an inline function might be instantiated as a callable function. Its all up to the compiler. In general it can easily happen that a compiler creates both an inlined and instantiated version of the very same function (no matter if its static or inlined).
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Reference: http://stackoverflow.com/questions/8982965/printing-in-mfc-application[^]
Question #1: I have a Dialog based app using sample code taken above. App runs fine. I want to avoid having the popup printer selection window appear once the print job is started (i.e. when PrintDocument() is called). I just want to print to the default printer. How can I do this?
Issue #2:
This dialog app itself creates numerous other new dialog windows depending on user's selection.
There is a need to have many of the features provided by this dialog application implemented as command line features.
What did I do? ...
Upon app started, I created a modeless dialog object with the intent not to display the dialog (unless absolutely necessary).
Some of the dialog methods do function. The method that handles the printing does not work.
The code fragment that causes a problem is CBatchResultsDlg::WaitForComplete() - because of AfxPumpMessage(). The owner of the CHtmlEditCtrl object is the Desktop window because setting the dialog window creating the object as owner fails.
How can I fix this such that my printing will work.
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Hello all. I'd like to set up, correctly, an UNIX (Ubuntu) environment so I can compile and test the network programs from the Unix Network Programming 3rd edition book by Richard Stevens. Please, I'm really lost. I don't know what to do.
modified 12-May-13 14:54pm.
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1. This has nothing to do with C++.
2. There is lots of help on Unix available via Google.
However, Richard Stevens books assume that you have a compiler and linker installed on your system. The most common one in use is gcc, free from here[^].
Use the best guess
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#include <stdio.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <strings.h>
#define MAXLINE 100
int main(int argc, char* argv[])
{
int sockfd, n;
char recvline[MAXLINE + 1]; /* string onde sera' colocado o dado */
struct sockaddr_in servaddr;
if(argc != 2)
{
fprintf(stderr, "utilizacao: daytime <endereco IP>");
}
if( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
fprintf(stderr, "erro no socket");
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(13); /* tempo do servidor */
/* inet_pton - convert IPv4 and IPv6 addresses from text to binary form */
if(inet_pton(AF_INET, argv[1], &servaddr.sin_addr)) < 0)
fprintf(stderr, "erro inet_pton para %s", argv[1]);
if(connect(sockfd, (SA*) &servaddr, sizeof(servaddr)) < 0)
fprintf(stderr, "erro de conexao");
while((n = read(sockfd, recvline, MAXLINE)) > 0)
{
recvline[n] = 0;
if(fputs(recvline, stdout) == EOF)
fprintf("erro de saida");
}
if(n < 0)
fprintf("erro de leitura");
}
I get lots of problems. In particular, I don't have the machine directory but I have installed gcc and build-essential:
In file included from /usr/include/x86_64-linux-gnu/machine/_types.h:34:0,
from /usr/include/x86_64-linux-gnu/sys/_types.h:33,
from /usr/include/x86_64-linux-gnu/sys/socket.h:37,
from /usr/include/netinet/in.h:25,
from /usr/include/arpa/inet.h:23,
from daytime.c:2:
/usr/include/x86_64-linux-gnu/i386/_types.h:79:3: note: previous definition of ‘__mbstate_t’ was here
In file included from /usr/include/netinet/in.h:25:0,
from /usr/include/arpa/inet.h:23,
from daytime.c:2:
/usr/include/x86_64-linux-gnu/sys/socket.h:39:28: fatal error: machine/_align.h: Arquivo ou diretório não encontrado
compilação terminada.
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I don't know why that directory has not been found. You need to go back to the build/install log for gcc and see if you can find out what happened.
Use the best guess
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so, is that a standard directory of UNIX? I found it quite strange too that's why I will install Ubuntu 13.04 (I'm using Ubuntu 12.10).
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