Managed C++/CLI

Working with date_t and time_t

10-Oct-16 22:53

Why have you posted this under Managed C++?

for study23-Sep-16 23:13

23-Sep-16 23:13

I am receiving a date structure in "24-9-2016 13:30" format. Now I want to convert time value to specific timezone, I am doing calculations and have number of hours to add or substract.

So I don't know: how can I initialize tm struct with the date value I have? how to add or substract hours in tc struct variable to get required date?

my intention is
Date received "24-9-2016 13:30" and 5 Hours to add so final Date: "24-9-2016 18:30"

C++

//Temporarily init time to local
time_t tempTime
time(&tempTime);
struct tm *initStruct = localtime(&tempTime);//initialize it with local time
//now modify it to user defined date
initStruct ->tm_year = 2016;
initStruct->tm_mon = 9;
initStruct->tm_hour = 13;
.
.
.
 //Not sure how can I subtract or add hours in this struc to get desired date value

please provide inputs.

modified 24-Sep-16 4:55am.

Richard MacCutchan23-Sep-16 23:53

23-Sep-16 23:53

I am not sure what this has to do with Managed C++. However, the time, _time32, _time64[^] function describes the content of a time_t value, which you can easily initialise with a user defined time. I have not come across a date_t type, where is it defined?

for study23-Sep-16 23:59

23-Sep-16 23:59

Sorry, if I used wrong group to post. I have updated post with some of the steps I tried, please check and let me know if is there any solution available.

Richard MacCutchan24-Sep-16 0:05

24-Sep-16 0:05

Since all those fields are integers you can add, subtract or replace any of them. You should check that the values are valid in terms of the calendar, although the mktime, _mktime32, _mktime64[^] functions will attempt to normalise a tm structure into a valid time. There are many other useful functions, and you should study the documentation to see which ones will help you.

for study24-Sep-16 0:33

24-Sep-16 0:33

Yes, all these are integers, so I can perform addition or subtraction, but it is not handled well in below cases-
if hours are added
Like 4.5 then 13 hours should become 18:30
Or more than 24 then date should modify

In above cases I will need to add additional code depending on hours value, which is bad, isn't there any system method which will modify entire structure depending on the value assigned

Richard MacCutchan24-Sep-16 0:58

24-Sep-16 0:58

If you want to add partial hours, days etc. Then use mktime (as I advised in my previous comment) to convert your tm structure into a time_t value. you can then just add or subtract the number of seconds in your time increment.

for study24-Sep-16 1:11

24-Sep-16 1:11

ok, so here is what I did now-

C++

//Temporarily init time to local

time_t tempTime
time(&tempTime);
struct tm *initStruct = localtime(&tempTime);//initialize it with local time
//now modify it to user defined date
initStruct ->tm_year = 2016;
initStruct->tm_mon = 9;
initStruct->tm_hour = 13;
//completed it...

int hoursToAdd = 4.5;

initStruct->tm_hour = initStruct->tm_hour + hoursToAdd;

time_t myTime = mktime(initStruct);//this return -1

printf( "%s", ctime( &myTime));//this prints null..

any idea whats going wrong here?

Richard MacCutchan24-Sep-16 1:29

24-Sep-16 1:29

C++

int hoursToAdd = 4.5;

That is not a valid statement so it will not even compile. You cannot assign a floating point number to an integer variable.

for study24-Sep-16 1:37

24-Sep-16 1:37

Yes, my bad. well in that case my original question reopens how can I assign partial hour to tm struct to enable it to give valid date value.

Richard MacCutchan24-Sep-16 1:48

24-Sep-16 1:48

You really (and I mean really) need to go and study the documentation which explains what each field represents. If you have some number of hours and some number of minutes then you need to add them separately to each field. You should also step through your code with the debugger so you can see at each step what are the values of the various fields.

for study25-Sep-16 20:18

Adding gtkmm lib to visual studio 2015

25-Sep-16 20:18

Thank you very much Richard for your kind help. I really appreciate your time and effort.

Osikwemen13-Sep-16 0:04

Osikwemen

13-Sep-16 0:04

Please I am new to c++ as I have been learning it on my own for months now, and I will like to know how to add the gtkmm lib to visual studio 2015. Any help will be much appreciated.thanks

Re: Adding gtkmm lib to visual studio 2015

Alexandre Bencz23-Sep-16 9:53

Alexandre Bencz

23-Sep-16 9:53

There is this experimental project of build the GTKmm with VS2015, take a look: GitHub - codekiddy2/Visual-Studio-gtkmm: Visual Studio 2015 Projects to build gtkmm from nowhere up to gtkmm itself[^]

MFC CDialogBar drawing issue on High DPI screen

Taiming J5-Sep-16 0:06

Taiming J

5-Sep-16 0:06

I have a MFC SDI application created and added CDialogBar to set as main toolbar as you look in the screenshot I attached. It works well on every windows os(Xp, 7, 8, 8.1, 10) of windows tablet devices except only Microsoft Surface.

Please look at this screenshot. the CDialogBar menu is cut off. I don't know reason why this happens. The drawing issue always only occurs on Microsoft Surface 3 which has high resolution and high DPI screen and it works good on any other tablet. This is very strange issue so I dragged toolbar(CDialogBar) and dropped down on any place then the toolbar was re-painted clearly. So.. through this issue, I am sure that this is re-drawing issue. Is there any drawing function to redraw that area?

I am attaching my minimized source code to represent drawing issue.

Drawing Issue Screenschot

Minimal Source code to represent drawing issue

Please help me. Thanks

Operating System: Windows 10
Tablet: Microsoft Surface 3
Tool: Visual Studio 2015 Update 3
DPI rate: 150%

To resolve this issue, I have been trying to set DPI Awareness property to None, but the graphics Interface was not good and they were all stretched. I really don't like this solution, I have to find other solution without setting DPI Awareness to "None".

Microsoft wants to hear about issues C++/CLI devs are having

John Schroedl23-Aug-16 9:28

Re: Microsoft wants to hear about issues C++/CLI devs are having

23-Aug-16 9:28

From the comments in this Visual Studio blog post: Visual Studio “15” Preview 4

Eric Battalio [MSFT] would like to hear from C++/CLI devs if there are issues we are having.

"We would like to learn more about issues developers have with C++/CLI. Please email me ebattali@microsoft.com"

I added another plea for a fix to the std::unique_ptr bug (can't pass it by value in /clr code). You may wish to add more. Please do so that he hears from us C++/CLI devs the minority that we are....

John

Richard Deeming23-Aug-16 9:31

Richard Deeming

23-Aug-16 9:31

This isn't really the right forum for your message, since it's not a question.

You should probably post it in The Insider News[^] instead. Smile | :)

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Re: Microsoft wants to hear about issues C++/CLI devs are having

John Schroedl23-Aug-16 9:34

Re: Microsoft wants to hear about issues C++/CLI devs are having

23-Aug-16 9:34

hmm, beg to differ in my interpretation of the purpose of this area. I marked it as Type: 'News' and this is listed as the Managed C++/CLI discussion area. That may explain a general lack of actual discussion however. I may post there too. Thanks

Richard Deeming23-Aug-16 9:50

Richard Deeming

23-Aug-16 9:50

Yes, but there's a reason the big red button at the top of this forum says "Ask a Question", rather than "New Discussion". Smile | :)

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

pin_ptr versus interior_ptr

John Schroedl23-Aug-16 9:04

Re: pin_ptr versus interior_ptr

23-Aug-16 9:04

I've used pin_ptr<> for years now but just came across interior_ptr<>. I supposed I may have been sheltered not needing it but can anyone illustrate why I'd prefer interior_ptr over pin_ptr?

John

Jon McKee31-Oct-16 17:29

Jon McKee

31-Oct-16 17:29

A wee bit late but if you're still curious:

interior_ptr<T> is useful if you need pointer arithmetic in managed code or a pointer that can reference a managed or native object. It doesn't pin the referenced object and instead gets updated by the CLR when the object moves just like a handle. Can be useful for some functions that can operate on managed and native objects as a native pointer can be passed to an interior_ptr<T> argument.

pin_ptr<T> is useful if you want a managed object that can be referenced by native code. It stops the GC from moving the object so the object's address can be safely assigned to a native pointer as long as the pin_ptr<T> is alive. You see this used a lot when people manually marshal System::String to a char*.

Cheers!

Re: pin_ptr versus interior_ptr

John Schroedl1-Nov-16 2:58