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QUESTION 1: are they the same? LPSTR and char *
QUESTION 2:
and what the heck is OLECHAR?
QUESTION 3:
I cant find the documentation for:
a. OLECHAR
b. LPSTR
QUESTION 4:
_TEXT()
_T()
QUESTION 5: if char is a Automation compliant data type, then why BSTR? and why Variant?
Thanks!
norm
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norm wrote:
what the heck is OLECHAR?
It's a macro which in a Unicode build places an L next to the string like this
L"this is my value";
This has the effect of creating a Unicode string.
LPSTR is a long pointer to a string, I believe it's the same as char *. Microsoft like to 'create' types with MACRO's, I guess that means they can change them later ( like WPARAM and LPARAM ).
norm wrote:
_TEXT()
_T()
Never seen them before. Looks to me like member variables on an example string class in MSDN. They sometimes use _ instead of m_.
norm wrote:
if char is a Automation compliant data type, then why BSTR? and why Variant?
A BSTR is a wide string, you'd set one with the L from OLECHAR above, otherwise you get a char *. A _bstr_t wraps both types for you. A VARIANT is a whole different kettle of fish, it carries a lot more than just strings.
Christian
No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
Hey, at least Logo had, at it's inception, a mechanical turtle. VB has always lacked even that... - Shog9 04-09-2002
Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002
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norm wrote:
QUESTION 1: are they the same? LPSTR and char *
That's the same. LPSTR is preferred if you want to minimize the * in the signatures (it's more object-like).
norm wrote:
QUESTION 2:
and what the heck is OLECHAR?
OLECHAR = WCHAR = 16-bits = UCS2 = Unicode (the OS uses unicode strings internally).
norm wrote:
QUESTION 3:
I cant find the documentation for:
a. OLECHAR
b. LPSTR
look in <wtypes.h>
norm wrote:
QUESTION 4:
_TEXT()
_T()
see <tchar.h>
This macro produces either a simple char* string or a WCHAR* string depending on whether you are compiling in "normal" mode (SBCS, DBCS, MBCS), or in UNICODE.
Use it instead of L"xxxx" which always produces a WCHAR* string regardless of the compilation mode.
Using _T(x) is also a good idea to remind yourself where are the hardcoded strings (internationalisation).
norm wrote:
QUESTION 5: if char is a Automation compliant data type, then why BSTR? and why Variant?
BSTR is an all-in-one string : Unicode, content itself, length.
A char* is not a typed string (can you figure out the codepage in it ? Answer = no). A char* does not have the length embedded (you could do a _tcslen(string) on it, provided it ends with a 0, etc., etc. ==> Many issues with a char*
VARIANT is a C-union struct. Introduced mostly because of VB (which hides all the type mapping for you) and other automation languages.
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thanks mike, will read them now.
norm
norm
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How do you get Visual C++.NET to recognize float data less than zero? For instance, if the following were typed:
float someint=(9/12); The program sees this as zero and not 0.75.
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put decimal points after the 9 and 12
-c
A conclusion is simply the place where someone got tired of thinking.
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9 and 12 are both integers, so that expression does integer division, thus the result is zero. Write it with floating-point constants:
9.0/12.0
to get the desired result.
--Mike--
"alyson hannigan is so cute it's crazy" -- Googlism
Just released - 1ClickPicGrabber - Grab & organize pictures from your favorite web pages, with 1 click!
My really out-of-date homepage
Sonork-100.19012 Acid_Helm
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hey everyone, i'm fairly new to MFC so forgive me if this is easy, but my View class is a CListView(in report mode) and i follow some i examples i found to get tabs working, by having a member varible in the View class and setting up the tabs in the view classes OnInitialUpdate, and now i have tabs but the header on the ListView apear over the tabs, which i want the list view to look like its in the tabs. any ideas?
should my View class be derived from tab class and create a ListView class in it? not the other way around? i tried a quick hack at that but got errors, but if that was right i'll have another go.
maybe i could make it draw the listview lower?
anyway thanks in advance.
Luke.
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Hi, everyone!
I am a newbie of MPEG4. First, I want to learn what is MPEG4.
Then I want to write a simple MPEG4 encoder/decoder. (Using C++)
But I can not find any documents and samples at hand.
Anyone know how can I find the resources?
(1. A step by step doc for newbie of MPEG4.)
(2. A simple encoder/decoder sample code.)
Thanks & nice weekend,
George
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Thanks, mariano pal!
It helps a lot.
Cheers,
George
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If i were you i would check out XviD.org. It's an opensource mpeg4 codec. You will probably not be able to write your own decoder cause that takes years and years of training. But start by looking at the xvid codec, it'll give you an idea of how hard it is 
good luck
-Rune Svendsen
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Thanks, Redeemer-dk!
It is a nice site!
Cheers,
George
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What are the ramifications of creating waitable timers for a scheduling utility (i.e. timers created using CreateWaitableTimer)? For instance, if you have 50 jobs and you create one waitable timer for each one in your scheduler, does this have any problems?
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Each timer is a kernel resource, albeit not a very big one.
Some questions:
- Is this a Windows Service or a standalone app?
- How far ahead are you sceduling? Seconds? Hours? Days?
- Are you queuing jobs, or letting them exist in parallel?
- How are you doing your timer "waits"?
- With
WaitForSingleObject or WaitForMultipleObjects? With the former, are you creating worker threads to "wait" on the timer firing?
- With the latter, how are you maintaining your "array" of timers?
- What's your timeout for the "waits"? INFINITE (yikes)?
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Anonymous wrote:
What are the ramifications of creating waitable timers for a scheduling utility (i.e. timers created using CreateWaitableTimer)?
I made it once and they have a behaviour worth of note: when you schedule something "on the past" (say, every 5 minutes, since yesterday), they won't lose a notificatio, i.e., you'll have in the previous example, 288 events being instantaneously fired (for all "missed" yesterday events).
I don't know if my example was clear, but it can be a good behaviour or a bad behaviour, depending on your use.
My latest article:
SQL Server DO's and DONT's[^]
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following one book I try to add another toolbar: belows is the new codes: (I had add all necessary resourses)
if (!m_wndBarSim.CreateEx(this, TBSTYLE_FLAT, WS_CHILD | WS_VISIBLE | CBRS_LEFT | CBRS_GRIPPER | CBRS_TOOLTIPS | CBRS_FLYBY | CBRS_SIZE_DYNAMIC) ||
!m_wndToolBar.LoadToolBar(IDR_TOOLBARSIMULATION))
{
TRACE0("Failed to create second toolbar\n");
return -1; // fail to create
}
It has no problem when combiling. But when run it, always :
" fail to create empty document "
could anyone answer this question?
Thanks
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My app starts an external program for the user. How can my app be notified when the external program exits, without tying up my app? I can't find any functions for "process end" callbacks 
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You need a handle to the process, which you can get as a return value from CreateProcess() or ShellExecuteEx(). Call WaitForSingleObject() and pass it the handle, and a timeout of 0. It will return WAIT_TIMEOUT while the process is running, and WAIT_OBJECT_0 when it closes.
--Mike--
"alyson hannigan is so cute it's crazy" -- Googlism
Just released - 1ClickPicGrabber - Grab & organize pictures from your favorite web pages, with 1 click!
My really out-of-date homepage
Sonork-100.19012 Acid_Helm
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in a reminder app i'm playin with i can't delete from the database and i don't understand. if i un comment the lines (test to read)
I get the required info, which means to me i'm on a recordset, but when i call delete it errors with no current recordset, what am i doing wrong?
BOOL CPageThree::DeleteRemind(CString sec, CString name)
{
CDaoDatabase datab;
CString SqlString;
int iRec = 0;
TRY
{
// Open the database
datab.Open("remind.mdb");
// Allocate the recordset
CDaoRecordset recset( &datab );
// Build the SQL statement
SqlString = "SELECT * "
"FROM Remind WHERE Catagory='";
SqlString += sec;
SqlString += "' AND Extra1='";
SqlString += name;
SqlString += "'";
// Execute it
recset.Open(dbOpenDynaset, SqlString, dbAppendOnly);
// make sure we can make changes and update
if (!recset.CanAppend() || !recset.CanUpdate( ))
AfxMessageBox("can't append from recordset");
// test to read from current recordset
// CString sWarnDate;
// recset.GetFieldValue("WarnDate",sWarnDate);
// delete the current record
recset.Delete();
// Close the database
datab.Close();
}
CATCH(CDBException, e)
{
// If a database exception occured, show error msg
AfxMessageBox("Database error: "+e->m_strError);
return FALSE;
}
END_CATCH;
GetDlgItem(IDC_BUT_DEL)->EnableWindow(FALSE);
InitTree();
return TRUE;
}
p.s am a beginner so be kind 
shotgun
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okay i got it, it was my dbAppendOnly, should be dbSeeChanges, of course
shotgun
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How do I find the height in pixels of what a combo box control *should* be? I am creating my own custom control, which includes combo list and list box sub-controls, and I want the user to be able to draw my control onto the dialog and have both sub-controls be the full width, and the list control be as tall as my custom control - the height of the combo box - a small gap between.
So I need to be able to calculate the size that the combo box should be in order to find the position and height of the list box below it....
Thanks!
- Kati
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1. A dialog box derived from CFontDialog doesn't call PreTranslateMessage!?
(Dialogs derived from CDialog or the common control dialogs always do).
This makes it difficult to provide Tooltip support in a CFontDialog derivation.
Does anyone know why - or how to add Tooltips?
2. Changing the Sample Text (Control ID stc5) only works initially. As soon as the font selection
is changed the Sample reverts to "AaBbYy" etc. How/can you subclass this control and "user"
set this text.
3. Ditto the position of this text on the CFontDialog seems to be "hardcoded" independently of Control ID stc5.
Moving the stc5 window in a resizable dialog doesn't move the Sample Text. Why??
gjr
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Hi,
I'm wondering if anyone can solve the closest pair problem in C/C++. "Closest Pair" problem is to find two points that are closest in a set of points. Of course we can use "brute search" by comparing each and every point but I need a faster algorithm than that (just like quicksort is faster than bubblesort).
Thank you 
Chris U.
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