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I wrote a function that open a registry key and than query some values - in fact there were three. Having full rights on it I observed something strange:
- the key opened successfully
- the first value failed to read
- the next two read OK
I tried to change the order of the values, but same result.
Each time the first read failed and returned error 234 -
//
// MessageId: ERROR_MORE_DATA
//
// MessageText:
//
// More data is available.
//
#define ERROR_MORE_DATA 234L // dderror
/* from winerror.h*/
I tried to reread the value after the failed attempt and - surprise - it worked! Why?
And what means the error code obtained first?
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You aren't initializing the parameters properly. Mostly likely, the parameter that indicates the size of the buffer you're providing for the data isn't initialized, or is initialized to 0.
Oh - and i have winerror.h. I don't have your code. Given that the problem is in the latter, it would be a good idea for you to post the relevant portions of that next time, rather than the system header file.
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Thanks!
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The code:
int RegReadLastRun(long *L){
HKEY hk;
DWORD RegType = REG_DWORD, size;
if(RegOpenKey(HKEY_LOCAL_MACHINE, reg0, &hk))return 1;
if(RegQueryValueEx(hk,reg1,NULL,&RegType,(unsigned char*)L,&size))return 2;
if(RegQueryValueEx(hk,reg2,NULL,&RegType,(unsigned char*)(&Inst),&size))return 3;
if(RegQueryValueEx(hk,reg3,NULL,&RegType,(unsigned char*)(&Uninst),&size))return 4;
if(RegCloseKey(hk))return 5;
return 0;}
reg1, 2 and 3 are DWORD
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As i suspected, you're not initializing size. It should be set to sizeof(DWORD) for a type of REG_DWORD.
Get used to reading the docs before blindly calling functions - it'll save you a lot of time and headaches.
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Thanks, buddy!
You see, sometimes when you are on a hurry, you make mistakes!
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OK. Now it works. Thanks a lot!
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Maybe the buffer you provided was not enough big to contain the whole key value, so you had to read twice before getting success...
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
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The code:
int RegReadLastRun(long *L){
HKEY hk;
DWORD RegType = REG_DWORD, size;
if(RegOpenKey(HKEY_LOCAL_MACHINE, reg0, &hk))return 1;
if(RegQueryValueEx(hk,reg1,NULL,&RegType,(unsigned char*)L,&size))return 2;
if(RegQueryValueEx(hk,reg2,NULL,&RegType,(unsigned char*)(&Inst),&size))return 3;
if(RegQueryValueEx(hk,reg3,NULL,&RegType,(unsigned char*)(&Uninst),&size))return 4;
if(RegCloseKey(hk))return 5;
return 0;}
reg1, 2 and 3 are DWORD
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As stated by MSDN:
LONG RegQueryValueEx(
HKEY hKey,
LPTSTR lpValueName,
LPDWORD lpReserved,
LPDWORD lpType,
LPBYTE lpData,
LPDWORD lpcbData
);
lpValueName
Pointer to a null-terminated string containing the name of the value to query.
hence reg1,reg2, reg3 have to be strings.
Moreover, MSDN says:
lpcbData
Pointer to a variable that specifies the size, in bytes, of the buffer pointed to by the lpData parameter. When the function returns, this variable contains the size of the data copied to lpData.
Hence you have to initialise size, for instance, if
L is defined as follows
long * L = new long[10];
then you have to set:
size = 10 * sizeof(long);
Incidentally last considerations show that your function signature is not correct, since you have to pass the buffer lenght too.
By the way, where come from Inst, Uninst?
Finally, the code is a bit messy... Maybe if you tell us exactly what you intend to do, we will show a cleaner sample.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
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OK. Now it works. Thanks a lot!
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You're welcome.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
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Read the docs carefully, the registry APIs are tricky. ERROR_MORE_DATA means the buffer you passed in isn't big enough to hold the data.
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The code:
int RegReadLastRun(long *L){
HKEY hk;
DWORD RegType = REG_DWORD, size;
if(RegOpenKey(HKEY_LOCAL_MACHINE, reg0, &hk))return 1;
if(RegQueryValueEx(hk,reg1,NULL,&RegType,(unsigned char*)L,&size))return 2;
if(RegQueryValueEx(hk,reg2,NULL,&RegType,(unsigned char*)(&Inst),&size))return 3;
if(RegQueryValueEx(hk,reg3,NULL,&RegType,(unsigned char*)(&Uninst),&size))return 4;
if(RegCloseKey(hk))return 5;
return 0;}
reg1, 2 and 3 are DWORD
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Hello everyone,
In Visual Studio 2005, I can not create Visual C++ Smart Device project -- when input required inputs (project name, path, etc.) in "New Project" dialog, then when I click OK, the "New Project" displays again -- without any error notifications...
And I have checked the related physical location of the project path, the project is not created.
I am wondering whether it is a bug of Visual Studio 2005, or I need to install some additional components in order to create Visual C++ Smart Device type project?
thanks in advance,
George
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Hi,
I want to read the call stack of another process and save it to a file.
I am able to atach to the process by using DebugActiveProcess but waht is the function which reads the info from the callstack and translates the symbol information
DavidR
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StackWalk64()
It's not quite trivial though - you'll want to read up on the DbgHelp API[^].
Alternately, just call MiniDumpWriteDump()[^], and use a debugger to examine the resulting dump.
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im using a performance counter to monitor my bandwidth but its not displaying like it does in performance monitor in my code it jumps from 0 to a 34523452(positive) number to a -45735399negittive) number in performance monitor it runs steady with what azureus says im uploading at when azureus says upload is around 226 KB/s performance monitor says around 244000 bytes/s here is the code that seems to not be right its running on a 1 sec timer
PDH_FMT_COUNTERVALUE fmtValue;
pdhStatus = PdhCollectQueryData(hQuery);<br />
if (ERROR_SUCCESS != pdhStatus)<br />
{<br />
ErrorExit("PdhCollectQueryData");<br />
cleanup();<br />
}<br />
<br />
pdhStatus = PdhCollectQueryData(hQuery);<br />
<br />
pdhStatus = PdhGetFormattedCounterValue (hCounter,<br />
PDH_FMT_DOUBLE,<br />
&ctrType,<br />
&fmtValue);<br />
<br />
if (pdhStatus == ERROR_SUCCESS)<br />
{<br />
sentinfo.Empty();<br />
sentinfo.Format("%.3d", fmtValue.doubleValue);<br />
GetDlgItem(IDC_SENT)->SetWindowText(sentinfo);<br />
UpdateWindow();<br />
}<br />
else<br />
{<br />
ErrorExit("PdhGetFormattedCounterValue");<br />
cleanup();<br />
}<br />
MSG msg;<br />
if(PeekMessage(&msg, 0, 0, 0, PM_REMOVE))<br />
{<br />
TranslateMessage(&msg);<br />
DispatchMessage(&msg);<br />
}
if you see what aint right please let me know.
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Since fmtValue.doubleValue is a float value, I do not think the "%d" format specifier is appropriate. You should try "%f" or "%g":
sentinfo.Format( "%.3f", fmtValue.doubleValue);
I hope this helps.
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where can i see a list of all the different one i can use %d %f %g %s %u ect.....?
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is it possible to capture parent window text(title bar text) instead of sending the title text from parent to child.
actually in our project we have more than 200 dialogs, and nw our client needs title bar look like parent text/child text.
for example say suppose we hav 3 dilaogs nd
1st dialog is parent of 2nd and 3rd dialogs and 2nd is parent of 3rd dialog so 3rd dialog is subchild for 1st dialog and child for 2nd dialog.
lets say
1st dialogs - title text is Dialog1
2nd dialogs - title text is Dialog2
3rd dialogs - title text is Dilaog3
and now the title text for each dialog should be as follows,
1st dialogs - title text is Dialog1
2nd dialogs - title text is Dialog1/Dialog2
3rd dialogs - title text is Dialog1/Dialog2/Dilaog3
itz just like directory sturcture which is displayed in addressbar while opening any directory.
as it is difficult to open every dialog and get the title text and send it to child and itz quite a bit confusion if there are sub-sub-sub dialogs so can we write any DLL to simply the problem if ny one hav idea regarding this plz lemme nw.
Raj Gopal
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In a dialog's OnInitDialog() you can call GetParent() to get the dialog's owner, and call GetWindowText() to get the owner window's caption text.
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thnx for reply sir.
But the problem here is there are many sub dialogs, actually for every dilaog the title should be
grandparent
grandparenttext/parent
grandparenttext/parent/child
grandparenttext/parent/child/subchild
grandparenttext/parent/child/subchild/subsubchild.....
so is it good way of creating a dll and pass the handle of the dialog and maintaing all the previous dilaogs handle in it so that we can loop thru the handles and get the title text of each dialog and put the text in the above format?
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You could paint the title bar yourself. This way you would not have to
change the title of your windows. Just would have to walk the parents
using GetParent, and build the new name for each window on the fly.
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