|
Sort of newbie question here. I've read in places that you should avoid returning large class objects (particulary the class String) or datastructures, and instead should call a function and send it back by reference. Like this (ExpressionData is a structure with 3 cstrings):
void CRatiosNewSearchStringDialog::GetExpressionData(SearchExpressionType & Expression)
{
Expression = ExpressionData;
}
as opposed to:
SearchExpressionType CRatiosNewSearchStringDialog::GetExpressionData()
{
return ExpressionData;
}
Where should I draw the line between a large and small piece of data i.e should I bother with all this for a single CString? When should I use return and when should I sent it back by reference? Advice?
|
|
|
|
|
I'm porting some code from gcc to VC++, and a macro I've used for years on gcc is giving me grief on VC++ (Visual Studio 2003).
#define swap16(x) \
({ \
unsigned __int16 __x = (x); \
((unsigned __int16)( \
(unsigned __int16)(((unsigned __int16)(__x) & (unsigned __int16)0x00ff) << 8) | \
(unsigned __int16)(((unsigned __int16)(__x) & (unsigned __int16)0xff00) >> 8) )); \
})
int _tmain(int argc, _TCHAR* argv[])
{
printf("%d\n", swap16(1);
return 0;
}
This code snippet generates several syntax errors. Any suggestions on resolving this issue are most welcome.
-Josh
|
|
|
|
|
joswr1ght wrote: Any suggestions on resolving this issue are most welcome.
Haven't used it for years but there used to be a compiler switch that produced files containing the expanded code.
led mike
|
|
|
|
|
led mike wrote: Haven't used it for years but there used to be a compiler switch that produced files containing the expanded code.
Are you referring to the /P option? It writes the preprocessor output to a .i file.
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
|
|
|
|
|
DavidCrow wrote: Are you referring to the /P option? It writes the preprocessor output to a .i file.
If it works I am, if not you are. 
led mike
|
|
|
|
|
Hmmm....why not just do this...
#define swap16(x) \
((unsigned __int16)( \
(unsigned __int16)(((unsigned __int16)(x) & (unsigned __int16)0x00ff) << 8) | \
(unsigned __int16)(((unsigned __int16)(x) & (unsigned __int16)0xff00) >> 8) ))
"Great job, team. Head back to base for debriefing and cocktails."
(Spottswoode "Team America")
|
|
|
|
|
I have a straightforward CPropertySheet with CPropertyPages. I need to reset the contents of page "A", depending on the settings on other pages, which means I need a way to catch when pages "open" and "close"
I can catch when a page "opens" by overriding OnChildActivate but I can't catch when a Page "closes". Any suggestions on a sane way to trap these events?
(Note, I know about OnInitDialog() for "open" or OnOk() for "close". Neither of these methods are guaranteed to be called when just bouncing back and forth between pages by clicking on tabs)
Thanks in advance.
|
|
|
|
|
On the pages themselves, you can override OnSetActive and OnKillActive and do whatever you need to do to the parent PropertySheet or other Property pages.
onwards and upwards...
|
|
|
|
|
hello,
I am building an application in VC 6wherein when the user clicks ona particular button, a query is fired to SQL SErver 2000 database and a report (crystal reports 8.5) is generated based on the data retrieved. I am having multiple clients which connect to the SQL server remotely. so while retrieving, i will need to specify the IP of the machine where the DB is stored.
I have heard of a function callled SetLogonInfo which allows a user to change the databse name on the fly. But when I add an Active X control to my app, the version of SetLogonInfo takes only 2 parameters...."void SetLogonInfo(short index, LPCTSTR lpszNewValue); ...instead of 4 which i have seen in most standard implementations. Could you please give me more details regarding this function and how do I connect remotely for crystal reports? What is the code that i need to include in this function?
Awating Your Reply
Thank You
|
|
|
|
|
|
I would like to use an initialization file to set some features of how my Visual C++ API will run. I would like to be able to set these from within the API to be used next time the application is started. Is there a "simple" solution?
|
|
|
|
|
You can use INI files, but I prefer by far using XML files, they are easy to use and also you can use the DTD files in order to check the correctness of everything.
You can also use the registry, but is far more complicated and then it is also more complicated to move the program from one PC to another one.
In order to use them you should check the articles here in CP, I'm sure that you can find lots of information on that.
Hope this helps.
|
|
|
|
|
Thank you, this did confirm my thoughts that an ini file could be used. Now I just need to know how to code for useing either the INI or the XML.
|
|
|
|
|
SimplCodr wrote: Now I just need to know how to code for useing either the INI or the XML.
if (ini_file_is_present)
use_ini_file();
else if (xml_file_is_present)
use_xml_file();
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
|
|
|
|
|
 Well that is exactly what I asked for isn't it. Thanks for the chuckle. Remember, I am an idiot and simpl is all I can do at this point. Lets see... How do I use an INI file or an XML file to set variables at program start? I'm still laughing...
|
|
|
|
|
SimplCodr wrote: How do I use an INI file...to set variables at program start?
WritePrivateProfileString() et al
For XML files, check out TinyXml.
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
|
|
|
|
|
Thank you. It looks like a good starting point for me.
|
|
|
|
|
Check out the appsettings class from p.j. naughter at www.naughter.com[^] Might be really close to what you want. Save and load ini, registry and xml.
Why is common sense not common?
Never argue with an idiot. They will drag you down to their level where they are an expert.
Sometimes it takes a lot of work to be lazy
|
|
|
|
|
Thanks for the suggestion. I am going to stick with the built in windows stuff that david mentions. A good resource I was not aware of.
|
|
|
|
|
Exactly!;P
LateNightsInNewry
|
|
|
|
|
Joan Murt wrote: You can also use the registry, but is far more complicated...
In terms of what? I consider the registry very easy to use and navigate through.
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
|
|
|
|
|
Yes, of course it is not a very hard thing to use... but I think it is easier to write data inside an XML because you have not to check the type of data that you want to write and read, you will never have the DTD and you will have to make a little more work if you want to move the application to another computer. Moreover you can edit any XML file with any editor and send it via mail to any of your customers if something fails sometime...
It is only a matter of tastes... I prefer the XML, after making a little wrapper class it is extremely easy to work with it and it is very powerful.
|
|
|
|
|
Forgive my Ignorance, I'm Eager to learn. Never heard of XML, or DTD Files. What are these wonderful items. I have always found using the registry directly the most straigt forward way, and also the easiest. At least one has a clear interface. Any layer between what you want to achieve and how you want to record what you want to achieve is a potential hazard, which will byte you back.
Store your settings under 'H_KEY\Local_Machine\Software\Joan_Murt\JoanMurtApp\Ver1.0\KEY
Me thinks that this is about as Uncomplicated as it can get.
Regards,
LateNightsInNewry
|
|
|
|
|
As I answered before it is only a matter of tastes... I prefer using XML files because as they are plain text files that can follow any structure they are very flexible, they are also easy to copy from one pc to another one, also you have the DTD files that allow you to control the correctness of the contents you placed in...
Take a look at the wikipedia on how to use it and why it is used: http://en.wikipedia.org/wiki/XML[^].
I've been using the registry also, but I find far more flexible and easy to deploy the XML files method...
Hope this helps.
|
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
