C / C++ / MFC

Re: How to write more that ONE data byte into ioctl file?

11-Apr-18 22:18

You do it like with any write operation to a file descriptor by passing a buffer and it's size:

C++

char buf[2];
// Assuming you need to write two 4 bit values passed as a byte
//  with sending the lower nibble first
buf[0] = data & 0x0f;
buf[1] = data >> 4;
write(file, buf, 2);

Vaclav_12-Apr-18 3:57

Vaclav_

12-Apr-18 3:57

Thank you.

app is not running in debug mode

Member 83893869-Apr-18 20:39

Member 8389386

9-Apr-18 20:39

Hello,
My 64 bit (VS 2013)application is not running in debug mode. Output log is:

"'

MainApp.exe' (Win32): Loaded 'C:\Windows\System32\msvcp120d.dll'. Cannot find or open the PDB file.
'MainApp.exe' (Win32): Loaded 'C:\Windows\System32\msvcp120d.dll'. Cannot find or open the PDB file.
'MainApp.exe' (Win32): Unloaded 'C:\Windows\System32\msvcp120d.dll'
'MainApp.exe' (Win32): Loaded 'C:\Windows\System32\msvcr120d.dll'. Cannot find or open the PDB file.
The thread 0x1bc8 has exited with code -1073741701 (0xc000007b).
The thread 0x2964 has exited with code -1073741701 (0xc000007b).
The thread 0x1040 has exited with code -1073741701 (0xc000007b).
The program '[9944] MainApp.exe' has exited with code -1073741701 (0xc000007b).

"

I tried to look over internet but could not find relevant answer. Can you please help to resolve it?

Maciej Los9-Apr-18 21:01

Maciej Los

9-Apr-18 21:01

Check this: 0xc000007b error

They say that your settings or setup got messed up and:

Quote:
I would suggest 2 things: first, try to reset your settings from Tools->import and export settings -> Reset all settings-> reset all settings, overwriting current settings.

If after that it still does not work, I would repair/re-install VS.

Victor Nijegorodov9-Apr-18 22:46

Victor Nijegorodov

9-Apr-18 22:46

Did you by chance mixed some native and managed parameter options?

Member 83893869-Apr-18 23:14

Member 8389386

9-Apr-18 23:14

may be....where is this option?

Inter Process Communication between C++ - C#

Victor Nijegorodov10-Apr-18 1:03

Victor Nijegorodov

10-Apr-18 1:03

Well, after re reading your OP I'm afraid I was wrong with my "hint".
It seems to more probable the reason is in a mixing some 32/64 bit settings or linked DLLs.

BTW, doe the Release 64 build work?
And Debug 32 build?

ptr_Electron8-Apr-18 18:13

ptr_Electron

8-Apr-18 18:13

I am working on C++ project where performance is critical. there is no logging mechanism. I dont want to implement logging in the same project as it will hit performance. And hence I want to create A C# project while takes care of actually logging from C++ process I will push the Log strings to C# process to do Actually logging.

I want to know which is the best IPC - Named pipes ? Memory Mapped files ? Socket
Which should not hit the performance

Could you please point me to some sample code/link which has the mechanism to Log from C++ to C# code please

Re: Inter Process Communication between C++ - C#

Jochen Arndt8-Apr-18 21:26

Re: Inter Process Communication between C++ - C#

8-Apr-18 21:26

Logging will not be a performance issue if you do that in an own thread. That thread may be part of the application itself or another application.

Using another application with IPC makes it more complicated and requires that the other application is running. So I would not use another application if there is no need for other communications besides logging.

There might be even no need of using a thread when logging does not occur at high rates with large data. The log data has to be prepared anyway within the time critical thread. Using then a log file which stays open might be sufficient. If you are concerned about the file write times, use overlapped IO so that the writing is done by the system in the background (which is basically the same as suggested above: moving the operation to another thread).

I know that the above is not what you asked for but I think it is helpful and you might find out that using IPC is not necessary. When maximum performance is a must-have, you have to use one of the above mentioned methods (own thread or overlapped IO) anyway even with IPC.

Randor 9-Apr-18 10:03

Randor

9-Apr-18 10:03

ptr_Electron wrote:
I want to know which is the best IPC - Named pipes ? Memory Mapped files ? Socket
Which should not hit the performance

On the Microsoft Windows platform the fastest possible logging is through Event Tracing for Windows (ETW)[^]. Logging with ETW so fast... graphics drivers can render at 150 FPS and perform logging at the same time without losing any framerate.

What it basically does is write integers into a circular buffer all in RAM. There is nothing faster.

ptr_Electron wrote:
Could you please point me to some sample code/link which has the mechanism to Log from C++ to C# code please

ETW logging msdn examples - Bing[^]

Best Wishes,
-David Delaune

Re: Inter Process Communication between C++ - C#

jschell14-Apr-18 5:48

jschell

14-Apr-18 5:48

ptr_Electron wrote:
I dont want to implement logging in the same project as it will hit performance.

I was involved in a C++ project years ago. Unix based. Performance was a contractual requirement.
The architect was sure that logging was a performance problem.

So we removed logging.
Absolute zero impact on performance.

And that was back when spewing stuff to a console (stdio) could impact performance.

If you have a performance problem then you need to address the requirements and design first before looking for problems in the implementation and technologies.

ptr_Electron wrote:
which has the mechanism to Log from C++ to C# code please

Every logging library that I have seen for at least the past 10 years if not longer uses pluggable designs. Which means if the plugs that are already available do not meet your needs then you can create your own. However at least when I looked some already supported remote logging plugs.

How cin.get() works in loop ?

Tarun Jha7-Apr-18 3:32

Tarun Jha

7-Apr-18 3:32

#include <iostream>
using namespace std;

int main(){
    char c;
    cin.get(c);                    //get a charecter from keyboard and assigns it to c

    while(c != '\n'){
        cout << c ;                 //displays the charecter on screen
        cin.get(c);                 //get another charecter
    }
}

int the code above shouldn't cout << c print every charecter i put in cin.get() in loop ?

Quote:
while(c != '\n'){
cout << c ; //displays the charecter on screen
cin.get(c); //get another charecter
}

instead it print the string i enter collectively, for ex.

Quote:

input : "Jhon simon"
output : "Jhon simon"

please explain

Thank you

David Crow7-Apr-18 6:34

David Crow

7-Apr-18 6:34

Your explanation is a bit unclear. If the "input:" and "output:" are the same, what exactly is the issue?

With limited information, the only thing I can suggest is:

cout << c << std::flush;

"One man's wage rise is another man's price increase." - Harold Wilson

"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons

"You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles

Richard MacCutchan7-Apr-18 20:55

Richard MacCutchan

7-Apr-18 20:55

No, it prints each character as you type it.

Peter_in_27808-Apr-18 21:13

Peter_in_2780

8-Apr-18 21:13

Google "cout buffering" for an explanation.

Software rusts. Simon Stephenson, ca 1994. So does this signature. me, 2012

CListCtrl with group view enabled and long subtitles

jfbode10291-Jun-18 12:16

jfbode1029

1-Jun-18 12:16

cin.get() does not read individual keystrokes -- the input is buffered by the terminal until you hit Enter, then all of the input is sent to the program at once.

To read individual keystrokes, you'll have to rely on a third-party tool like GNU's ncurses library.

Friedbert Widmann5-Apr-18 22:43

Friedbert Widmann

5-Apr-18 22:43

I use the CListCtrl to display a list of grouped properties. Each of these groups should be described by an explanatory text. That's why I entered longer texts as subtitles for the groups.
If the subtitle is short enough that it fits in one line, then everything looks fine.
However, if the subtitle is longer than one line, it is wrapped at the width of the list control. Unfortunately, the wrapped lines are then superimposed by the following contents of the list.
For example, the content of the items of the group overwrite the wrapped subtitle. When the group is collapsed, the subtitle is superimposed by the following groups.

See also the examples in the following Screenshot:

Group 1 has a short subtitle and all looks fine.
Group 2 has a log subtitle, which is overwritten by the contents of the items.
Group 3 is collapsed and the wrapped subtitle is overwritten by the content of group 4.

Is there a way to expand the area for the subtitles?

Regards,
Friedbert

How can I initialize an array of structs where the array size is set at compile time?

arnold_w5-Apr-18 21:46

Re: How can I initialize an array of structs where the array size is set at compile time?

5-Apr-18 21:46

How can I do this in a smarter way in regular C-programming, without having an init function that initializes the values?

C++

struct myStruct_s {
    int myInt;
    Bool_t myBool;
    EventCallback_t myEventCallback;
};

#define DESIRED_ARRAY_SIZE    (5)

static struct myStruct_s myArray[] = {
#if 1 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 2 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 3 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 4 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 5 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 6 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 7 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 8 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 9 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 10 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 11 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 12 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 13 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 14 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 15 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 16 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 17 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 18 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 19 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
#if 20 <= DESIRED_ARRAY_SIZE
    {0xABCD, TRUE, NULL},
#endif
};

modified 6-Apr-18 7:29am.

Richard MacCutchan5-Apr-18 23:26

Richard MacCutchan

5-Apr-18 23:26

Please edit the above, and remove all that formatting. People here can read normal font sizes quite well.

Re: How can I initialize an array of structs where the array size is set at compile time?

arnold_w6-Apr-18 0:31

Re: How can I initialize an array of structs where the array size is set at compile time?

6-Apr-18 0:31

I didn't use any formatting. The forum has a bug, it does weird things to the formatting if you start a line with either #define of #if (try for yourself).

Jochen Arndt6-Apr-18 0:55

Re: How can I initialize an array of structs where the array size is set at compile time?

6-Apr-18 0:55

If you know HTML and want to insert HTML tags manually when posting (besides using the options on top of the editor window) have a look at the bottom of the page when posting a message. There are two options:

"Treat my content as plain text, not as HTML"
and
"Use Markdown formatting"

When both are unchecked nothing will be auto formatted.

The first option can be also changed on your profile settings page in the Forums tab.

arnold_w6-Apr-18 1:30

Re: How can I initialize an array of structs where the array size is set at compile time?

6-Apr-18 1:30

Thanks.

Jochen Arndt5-Apr-18 23:36

Re: How can I initialize an array of structs where the array size is set at compile time?

5-Apr-18 23:36

When using C++ and all members should be initialised with the same value you can provide a constructor:

C++

struct myStruct_s {
    int myInt;
    Bool_t myBool;
    EventCallback_t myEventCallback;
    myStruct_s() : myInt(0xABCD), myBool(FALSE), myEventCallback(NULL) { }
};

static struct myStruct_s myArray[DESIRED_ARRAY_SIZE];

arnold_w6-Apr-18 0:32