ATL / WTL / STL Discussion Boards

KRISHNARAYALU16-Jun-13 20:46

16-Jun-13 20:46

Hi Guys,

Reading about COM Threading since two days..
But still i Couldnt understand Exactly " What is an Apartment ".

Kindly can any one explain in simple terms or show some source to understand more.

Thanks,

TV Krishna Rayalu

Re: COM Apartment

Richard MacCutchan16-Jun-13 20:57

Richard MacCutchan

16-Jun-13 20:57

A good description can be found on this MSDN page[^]. Basically it is whether the COM object can support multi-threading or not: crazy Microsoft terminology again.

Use the best guess

Re: COM Apartment

KRISHNARAYALU16-Jun-13 21:10

KRISHNARAYALU

16-Jun-13 21:10

Thanks Richard.

That link is informative.
i could able to understand STA and MTA, i got more discription
on what STA and MTA do then what exactly Apartment is.
Can you please define it in simple words.

Thanks & Regards,
TV Krishna Rayalu

Re: COM Apartment

Richard MacCutchan16-Jun-13 21:24

Richard MacCutchan

16-Jun-13 21:24

KRISHNARAYALU wrote:
Can you please define it in simple words.

Define what? The link I gave you uses fairly simple words, and explains exactly what the difference is. If you do not understand the difference between single-threaded and multi-threaded code, then you should avoid using COM.

Use the best guess

Re: COM Apartment

KRISHNARAYALU16-Jun-13 21:35

KRISHNARAYALU

16-Jun-13 21:35

Richard,
I may missed something vital in that article or Some basic in that concept.
I will re read the article. Thanks for Support.

Thanks & Regards,
TV Krishna Rayalu

Re: COM Apartment

imagiro4-Jul-13 2:53

imagiro

4-Jul-13 2:53

First of all an apartment is an abstract concept, means, there is no physical thing behind. When a thread starts it decides in which apartment it wants to "live". It does so by calling CoInitialize or CoInitializeEx.

An apartment is a kind of a convention how to handle things. A thread that initializes a single-threaded apartment states, that it does not allow any other threads to enter the same apartment. COM knows then, that all objects living in this apartment can be accessed only from this same thread and makes sure that these objects are used only from within this thread.

A thread that initializes a multi-threaded apartment allows other threads. COM knows then, that multiple threads might access the objects in this apartment and relies on these objects to handle thread synchronization by themselfs.

So how do other threads enter the same apartment? Simply also via CoInitializeEx. By requesting a multi-threaded apartment they will automatically resist in the same apartment as the other MTA threads since there can only be one MTA.

So in the end each thread that initializes a STA creates its own apartment, while threads initializing MTA enter the one and only MTA. And the same is of course valid for all COM objects created from this thread.

Re: COM Apartment

Krishnakumartg13-Aug-13 6:53

Krishnakumartg

13-Aug-13 6:53

http://docs.eiffel.com/sites/docs.eiffel.com/files/images/com-2.gif[^]

how to export an enum type in an ATL prject

astupidboy12-Jun-13 21:58

astupidboy

12-Jun-13 21:58

my code:

XML

class ATL_NO_VTABLE CSysLog :
    .....
{
public:
    [export]
    enum EnumLogLevel
    {
        LogNone = 0,
        LogError = 1,
        LogWarning = 2,
        LogInfo = 3,
        LogDebug = 4,
        LogDebug1 = 5,
        LogDebug2 = 6,
        LogDebug3 = 7,
        LogDebug4,
    };
......

it takes errors likes:
c1xx : error C3174: ....
LINK : fatal error LNK1250: ...
how to correct it?

Re: how to export an enum type in an ATL prject

Jonathan Davies15-Jun-13 4:10

Jonathan Davies

15-Jun-13 4:10

Declare it in IDL e.g.

typedef [v1_enum] enum LogLevel // These are the possible levels of log
    {
        None = 1,
        Error = 2,
        Warning = 3
    }LogLevel;

Use it in an interface parameter if you need to export a method:

C++

interface IMyErrors : IDispatch {
            HRESULT GetCurrentError(LogLevel udtLevel,...
...

Compile and and export as a type library or .dll or import the IDL into a .h file

Here is a C Program showing some Error, Give some solution

Member 969295410-Jun-13 4:03

Member 9692954

10-Jun-13 4:03

#include<stdio.h>
#include<conio.h>

int *val1,*val2;
int *oper;

void calc(val1,val2,oper)
{
switch(*oper)
{
case '+':printf("%d",*val1+*val2);
break;

case '-':printf("%d",*val1-*val2);
break;

case '*':printf("%d",*val1 * *val2);
break;

case '/':printf("%d",*val1 / *val2);
break;
default:printf("invalied input");

}
}
void main()
{
int num1,num2;
int oper1;
printf("Enter 2 number and an operator\n");
scanf_s("%d%d%d",&num1,&num2,&oper1);
//fflush(stdin);
calc(&num1,&num2,&oper1);
_getch();
}

it is showing all of the following ERRORS

Error   2   error C2017: illegal escape sequence    c:\users\lina\desktop\project7\project7\source.cpp  33  1   Project7
Error   1   error C2448: 'calc' : function-style initializer appears to be a function definition    c:\users\lina\desktop\project7\project7\source.cpp  8   1   Project7
Error   3   error C3861: 'calc': identifier not found   c:\users\lina\desktop\project7\project7\source.cpp  33  1   Project7
    6   IntelliSense: variable "oper" is not a type name    c:\Users\Lina\Desktop\Project7\Project7\Source.cpp  7   21  Project7
    4   IntelliSense: variable "val1" is not a type name    c:\Users\Lina\Desktop\Project7\Project7\Source.cpp  7   11  Project7
    5   IntelliSense: variable "val2" is not a type name    c:\Users\Lina\Desktop\Project7\Project7\Source.cpp  7   16  Project7

Re: Here is a C Program showing some Error, Give some solution

Richard MacCutchan10-Jun-13 6:03

Richard MacCutchan

10-Jun-13 6:03

Please format the code block properly, and identify line 33.

Use the best guess

Re: Here is a C Program showing some Error, Give some solution

Krishnakumartg13-Aug-13 7:05

Krishnakumartg

13-Aug-13 7:05

Replace

int *val1,*val2;
int *oper;
 
void calc(val1,val2,oper)

with

//int *val1,*val2;
//int *oper;

void calc(int* val1,int* val2,int* oper)

std::map and error checking

bkelly139-Jun-13 10:42

bkelly13

9-Jun-13 10:42

Windows 7, Visual Studio 2008, MFC, C++, Dialog

My application makes use of an std::map, inserting records with the following:

m_tmats_definition_map[ the_key ] =  m_one_definition_record;

the_key is a CString and m_one_definition_record is a structure of several CStrings and a few various fields such as integers.

That seems to be working. Now in the event something does not work out right I want some error checking. I am not finding much of anything concerning run time checking on this insert operation. Probably not looking in the right places or using the right search phrase. Where can I look to find a good discussion on this topic?

Thanks for your time
If you work with telemetry, please check this bulletin board: http://www.bkelly.ws/irig_106/

Re: std::map and error checking

Garth J Lancaster9-Jun-13 13:18

Garth J Lancaster

9-Jun-13 13:18

ouch - hard question - I just had a look and its a right PITA - 'Dinkumware' and SGI used to have good manuals (and even finding what exceptions are thrown within is hard enough)

SGI's manual page for MAP is ... http://www.sgi.com/tech/stl/Map.html[^]

that may give you a start point - what sort of error's do you expect ? dont forget that map doesnt throw an error for a duplicate key value (the commonest issue I guess) - it simply replaces the existing value... for that reason, you should use find() first on the map to see if the value already exists

'g'

Re: std::map and error checking

bkelly139-Jun-13 14:16

bkelly13

9-Jun-13 14:16

I don't know what sort of errors to expect. Isn't that one of the joys of software? <grin>
Good link.
Good point with the Find(). I do want to know if there are duplicates and will incorporate that.

Thanks for your time
If you work with telemetry, please check this bulletin board: http://www.bkelly.ws/irig_106/

Re: std::map and error checking

Richard MacCutchan9-Jun-13 21:23

Richard MacCutchan

9-Jun-13 21:23

You need to check return values of function calls that provide information. See here[^] for the insert function.

Use the best guess

Re: std::map and error checking

MicroVirus11-Jun-13 12:07

MicroVirus

11-Jun-13 12:07

In this case, there's nothing you need to do. If something goes wrong, it'll throw a C++ exception. Most likely causes will be that a new element can't be constructed, or that there is insufficient memory.
But maybe this is not what you meant. You say you want error checking; why do you want error checking? What is that you want to accomplish? Perhaps the solution is different.

status display in a dialog

bkelly139-Jun-13 5:17

bkelly13

9-Jun-13 5:17

Windows 7, Visual Studio MFC, C++, dialog based project

A dialog is to have a status display area. The code will add lines of text. My preference is for each new line of text to be added to the bottom and have the display scroll up. The user will not be able to edit the text, but it would be nice to be able to capture it with ctl-c to paste somewhere else.

I tried an edit control but each update wipes out the previous text.
List box seems to be the simplest control, yet still has many user accessible features.

I would like to read your reccomendations.

Thanks for your time
If you work with telemetry, please check this bulletin board: http://www.bkelly.ws/irig_106/

Re: status display in a dialog

Garth J Lancaster9-Jun-13 14:53

Garth J Lancaster

9-Jun-13 14:53

have a look at this - its what I used for years when I did MFC

A Logging Listbox Control[^]

[edit] I can probably remember how to use it in a Dialog based app if you think you want to use it
Joseph's site is http://www.flounder.com/logctl.htm[^] [/edit]

'g'

std::map, fundamental get started problem RESOLVED

bkelly139-Jun-13 4:04

bkelly13

9-Jun-13 4:04

Windows 7, Visual Studio 2008, MFC, CPP, std::map
I am trying to get an std::map working. I have tried several permutations and patterned it after some tutorials found with a search. Still I am unable to get it right and to decipher the error message.
Please assist with this problem.
The setup

XML

typedef struct
{
   unsigned int   identifier_location;
   unsigned int   count_found;
   CString        key;
   CString        token[ MAX_TOKEN_COUNT ];
}     td_tmats_attributes_definitions;

td_tmats_attributes_definitions    m_one_definition_record;

std::map < CString, td_tmats_attributes_definitions > m_tmats_definition_map;
//          ^ the key    ^the data to store
// below is an alternate declaration.
std::map < string, td_tmats_attributes_definitions > m_tmats_definition_map_string;

And now the code

CString  the_key;
…
The code:
// The primary insertion code
 m_tmats_definition_map.insert( the_key, m_one_definition_record );
// the alternate
string str_key = the_key;
//            m_tmats_definition_map_string.insert( the_key, m_one_definition_record );

Neither of the two options will compile.

I was prepared to post the error message, but I have a strong suspicion that reader will know my error with little effort and the long text from VS output box will only clutter things up. Let me know if you want to see the error text.

Please tell me what I need to change.

Thanks for your time
If you work with telemetry, please check this bulletin board: http://www.bkelly.ws/irig_106/

modified 9-Jun-13 12:44pm.

Re: std::map, fundamental get started problem

pasztorpisti9-Jun-13 4:19

pasztorpisti

9-Jun-13 4:19

C++

m_tmats_definition_map.insert( std::make_pair(the_key, m_one_definition_record) );

C++

m_tmats_definition_map[the_key] = m_one_definition_record;

std::make_pair should be in the <utility> include.

Re: std::map, fundamental get started problem RESOLVED

bkelly139-Jun-13 4:46

bkelly13

9-Jun-13 4:46

As you already know, that compiles. I see the second option as being a bit more clear and used it.
Thank you for your time.

Thanks for your time
If you work with telemetry, please check this bulletin board: http://www.bkelly.ws/irig_106/

CFileException, discover reasons RESOLVED

bkelly138-Jun-13 10:05

bkelly13

8-Jun-13 10:05

Windows 7, 64 bit, Visual Studio 2008, MFC, C++

After a long series of searches looking for a nice method of reading from a text file into CString I arrived at the following:

<br />
CStdioFile definition_file;<br />
try<br />
      {<br />
         definition_file.Open( m_definition_file_name, CFile::modeRead );<br />
      }<br />
      catch( CFileException e )<br />
      {<br />
         e.m_cause;<br />
      }<br />

This is from the VS help utility:

<br />
catch( CFileException* e )<br />
{<br />
   if( e->m_cause == CFileException::fileNotFound )<br />
      printf( "ERROR: File not found\n")<br />
   e->Delete();<br />
}<br />

This leads to the concept

<br />
if( e->m_cause == CFileException::fileNotFound )<br />
      printf( "ERROR: File not found\n");<br />
elseif( e->m_cause == CFileException::generic )<br />
      printf( "ERROR: An unspecified error occurred.\n");<br />
elseif  etc etc<br />

Is there a better way of capturing the text of the error rather than an if/else/else/else sequence?
Note: I am open to any type of suggestion. The goal is to read a CSV text file and parse it into a std::map.

Thanks for your time
If you work with telemetry, please check this bulletin board: http://www.bkelly.ws/irig_106/

Re: CFileException, discover reasons

Richard MacCutchan8-Jun-13 21:40

Richard MacCutchan

8-Jun-13 21:40

Use the GetErrorMessage[^] member function.

Use the best guess

Re: CFileException, discover reasons RESOLVED

bkelly139-Jun-13 3:54

bkelly13

9-Jun-13 3:54

Cool.
Thank you.

Thanks for your time
If you work with telemetry, please check this bulletin board: http://www.bkelly.ws/irig_106/

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.