C / C++ / MFC Discussion Boards

Re: How know if a window is above another

Rick York15-Dec-17 6:09

15-Dec-17 6:09

Try calling EnumDesktopWindows. I think it will give the window handles in their z-order to the callback function. I am not sure about this though. It would be fairly easy to contrive a test app to experiment with it. You might find EnumWindows will do it also. Between the two you should be able to determine what you want. Once you get the window handles in their z order you will have to determine which window is which, likely by their titles.

Re: How know if a window is above another

Victor Nijegorodov15-Dec-17 9:28

Victor Nijegorodov

15-Dec-17 9:28

this discussion could also help: c# - How to get the z-order in windows? - Stack Overflow

Re: How know if a window is above another

Schehaider_Aymen15-Dec-17 11:07

Schehaider_Aymen

15-Dec-17 11:07

I need smthing that works with c++. Smile | :)

"The Only Limit Is Only Your Imagination."

Re: How know if a window is above another

Richard Andrew x6416-Dec-17 3:15

Richard Andrew x64

16-Dec-17 3:15

If you can do C++, then you can surely translate from C#. Especially since the functions you need to call are right in the code. Roll eyes | :rolleyes:

The difficult we do right away...
...the impossible takes slightly longer.

Re: How know if a window is above another

leon de boer16-Dec-17 5:36

leon de boer

16-Dec-17 5:36

Windows API has the function GetTopWindow
GetTopWindow function (Windows)[^]

From the TopWindow you want walk down thru the chain via GetNextWindow
GetNextWindow function (Windows)[^]

So in your case you want to ask the topWindow of the window that contains both FileZilla window and a Notepad Window. You can then walk along the chain using GetNextWindow and see which is above which just by asking the window title.

Something like this will work

C++

char buf[256];
HWND Wnd = GetTopWindow( /*handle of window containing both*/ );
GetWindowText(Wnd, &buf[0], sizeof(buf));
while (Wnd != 0 && !stricmp(&buf[0], "FileZilla") && !stricmp(&buf[0], "NotePad"))
{
   Wnd = GetNextWindow(Wnd, GW_HWNDNEXT); // Next window
   GetWindowText(Wnd, &buf[0], sizeof(buf)); // Get it's title
}
if (Wnd == 0) {
   /* Error neither window found */
}
else {
   /* Wnd is the topmost of 2 windows title and the string title is in buf */  
}

It is equivalent to
EnumChildWindows function (Windows)[^]
However for the simplicity you have it isn't worth setting up the enumeration function.

In vino veritas

Frame or even Thread exception handler with _try _except/_catch()

ForNow15-Dec-17 3:22

ForNow

15-Dec-17 3:22

Is there an Api to implement exception handling on function/frame thread basis without the _try _except/_catch statements as that limits me to only certain type of exceptions

It would be nice to have an api on a function or frame Even on a thread basis

The function and the frame saves the programmer from doing unwinding

with AddVectoredExceptionHandler I catch everything but then I have to figure out from which function the exception occurred

Thanks

How to check session created or not in MySQL X DevApi A,k,a X Protocol.

lynxpravoka14-Dec-17 12:49

lynxpravoka

14-Dec-17 12:49

it's been 2 days. i'm struggle with this things. this's still new. the documented it just only help a bit. i want to check session created or not. a.k.a Connected or not. i don't know why the developer MySQL make new terms to call a thing. in this code. everytime i change something credential thing like host, port, user,pass. it return same. and return unexpected result with long zero 00000000000000 if use cout to sess. in my server i already enable X Plugin. my enviroment is Visual Studio Community 2017 c++ desktop.

C++

#include <iostream>
#include "mysql_xapi.h"

using namespace std;

int main()
{
// initiliziation 
	mysqlx_session_t  * sess;
	char conn_error[MYSQLX_MAX_ERROR_LEN];
	int err_code;
// open session. i use port 3306 cause this my mysql default port run. but in documented it says default port is 33060. i don't know it's seperate port to access. but when i change it to 33060. the result still same.

	sess = mysqlx_get_session("127.0.0.1", 3306, "root", "root", "test", conn_error, &err_code);

	if(!sess)
{
cout << "It's not connect";
}
else
{
cout << "It's connect";
}

// close session
	mysqlx_session_close(sess);
	return 0;
}

Re: How to check session created or not in MySQL X DevApi A,k,a X Protocol.

Jochen Arndt14-Dec-17 21:01

Jochen Arndt

14-Dec-17 21:01

The function provides an error code and an error message upon failure. So print those out to get information on what went wrong:

sess = mysqlx_get_session("127.0.0.1", 3306, "root", "root", "test", conn_error, &err_code);
if (NULL == sess)
{
    cout << "Connection failed; error " << err_code << ": " << conn_error << endl;
}

Re: How to check session created or not in MySQL X DevApi A,k,a X Protocol.

lynxpravoka15-Dec-17 2:34

lynxpravoka

15-Dec-17 2:34

The error nothing helping. it shows string unexpected result and integer 1.

can u figure out when the error like that? i think can't.

Re: How to check session created or not in MySQL X DevApi A,k,a X Protocol.

Jochen Arndt15-Dec-17 2:51

Jochen Arndt

15-Dec-17 2:51

I would expect a meaningful error message if one the parameters is wrong.

That generic message might indicate that it is networking problem. Because you are using localhost (127.0.0.1) it is probably not due to blocking by a firewall. You should check the port number and ensure that it is the port on which your server is listening.

Depending on the operating system, you might also us a command line utility to show listening ports (as root/adminstrator: Linux: lsof -nPi, Windows: netstat -ban).

C pre increment and post increment

Anonygeeker13-Dec-17 23:27

Anonygeeker

13-Dec-17 23:27

Hi,
int x=11;
printf("%d %d %d ", x++,++x,++x);

It prints 13 14 14, But I thought 13 14 15
Why ?

Re: C pre increment and post increment

Richard MacCutchan13-Dec-17 23:52

Richard MacCutchan

13-Dec-17 23:52

Because you should never use such expressions. The compiler writers are allowed to handle the order of incrementation in any way they like, so the results may or may not be what you expect. Bottom line: don't do it.

Re: C pre increment and post increment

Anonygeeker14-Dec-17 1:05

Anonygeeker

14-Dec-17 1:05

I agree. but my doubt was how it happens.

Re: C pre increment and post increment

Jochen Arndt14-Dec-17 0:01

Jochen Arndt

14-Dec-17 0:01

It is executed in this order here:

C++

// Pre-increment is executed first
++x; // 12
++x; // 13
// push first parameter on the stack: 13
push x; 
// post increment
x++; // 14
// push 2nd and 3rd parameter on the stack: 14
push x; 
push x;

Re: C pre increment and post increment

Anonygeeker14-Dec-17 1:05

Anonygeeker

14-Dec-17 1:05

Good explanation..Thanks

Re: C pre increment and post increment

leon de boer14-Dec-17 6:16

leon de boer

14-Dec-17 6:16

It isn't a good answer it's wrong the result is undefined.

Try it on VS2017 and you will likely get "13 13 13 " because of the way the optimizer works.

In vino veritas

Re: C pre increment and post increment

Daniel Pfeffer14-Dec-17 2:00

Daniel Pfeffer

14-Dec-17 2:00

This expression is undefined by the C Standard, meaning that the compiler can do anything with it, including formatting your disk or causing demons to fly out of your nose. You should consider yourself lucky that the compiler only incremented 'x' in a weird manner. Smile | :)

Note that even changing the compiler options (e.g. optimization) might change the printed results, so even if this "appears to work properly" on your system - DON'T DO IT!

(On comp.std.c and comp.lang.c they used to refer to a notional system, the DeathStation 9000, that would actually create Nasal Demons when it encountered undefined expressions Smile | :)

)

If you have an important point to make, don't try to be subtle or clever. Use a pile driver. Hit the point once. Then come back and hit it again. Then hit it a third time - a tremendous whack.

--Winston Churchill

Re: C pre increment and post increment

Anonygeeker14-Dec-17 17:15

Anonygeeker

14-Dec-17 17:15

thank you .. Smile | :)

wchar_t in C

Anonygeeker13-Dec-17 22:18

Anonygeeker

13-Dec-17 22:18

Hi,

Is there a data type wchar_t in C?If so, how it differ from char?

Re: wchar_t in C

CPallini13-Dec-17 22:44

CPallini

13-Dec-17 22:44

Quote:
Is there a data type wchar_t in C?

Yes, apparently[^].

Quote:
If so, how it differ from char?

It is compiler dependent.

Re: wchar_t in C

Jochen Arndt13-Dec-17 22:50

Jochen Arndt

13-Dec-17 22:50

Yes, since C90.

See wchar_t - C++ Reference[^] and Wide character - Wikipedia[^].

Because it is implementation defined (compiler and platform dependant), there is no general answer to how it differs from a char.

Re: wchar_t in C

Anonygeeker13-Dec-17 23:51

Anonygeeker

13-Dec-17 23:51

Thanks. I tried finding size of it and got 4 bytes. If so, It should be able to take something like "abc". But its not happening. Why?

Re: wchar_t in C

Jochen Arndt14-Dec-17 0:09

Jochen Arndt

14-Dec-17 0:09

Because "abc" is a char* string and not a wchar_t which represents a single character.

wchar_t are used to store fixed length Unicode characters like UTF-16 or UTF-32 while char can store fixed length ASCII or ANSI characters (with an associated code page) or variable length characters like UTF-8 or Microsoft multi byte characters.

Re: wchar_t in C

jschell14-Dec-17 8:48

jschell

14-Dec-17 8:48

Jochen Arndt wrote:
wchar_t are used to store fixed length Unicode characters like UTF-16 or UTF-32

Just noting that statement is somewhat of a generalization.

For starters, unicode, for those bit sizes never represents all characters via single character. One needs to go to 128 bits for a full representation. Maybe that isn't even big enough.

Additionally it is not limited to unicode. Although perhaps these days that would be the predominant usage in the western world.

Re: wchar_t in C

Jochen Arndt14-Dec-17 11:46

Jochen Arndt

14-Dec-17 11:46

Quote:
"wchar_t are used to store fixed length Unicode characters like UTF-16 or UTF-32"

Just noting that statement is somewhat of a generalization.

Why? As far as I know wchar_t is not used for variable length encodings.

jschell wrote:
for those bit sizes never represents all characters via single character

While that is true for UTF-16 it is not for UTF-32.

jschell wrote:
One needs to go to 128 bits for a full representation

That is wrong.

The Unicode Blog: Announcing The Unicode® Standard, Version 10.0[^]:
Tuesday, June 20, 2017

Version 10.0 of the Unicode Standard is now available. For the first time, both the core specification and the data files are available on the same date. Version 10.0 adds 8,518 characters, for a total of 136,690 characters. These additions include four new scripts, for a total of 139 scripts, as well as 56 new emoji characters.

Still 14 of 32 bits unused.

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