C / C++ / MFC

Re: C4244 conversion from 'double' to 'float' warning

19-Mar-09 7:21

penny black wrote:
Is only remedy to initialize htmin as double?

An explicit cast will do the trick

htmin = static_cast<float>(atof(value));

BTW atof is just an axample of misnamed function.
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

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-- Iain Clarke

[My articles]

modified on Thursday, March 19, 2009 2:46 PM

Eytukan19-Mar-09 7:29

Eytukan

19-Mar-09 7:29

another way to eat the warning Cool | :cool:

std::istringstream b("100.003133");
float f1;
b >> f1;

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

Re: C4244 conversion from 'double' to 'float' warning

CPallini19-Mar-09 7:38

Re: C4244 conversion from 'double' to 'float' warning

19-Mar-09 7:38

very good, indeed.
Smile | :)

penny black19-Mar-09 7:36

Re: C4244 conversion from 'double' to 'float' warning

19-Mar-09 7:36

static_cast gave me syntax error.

CPallini19-Mar-09 7:41

Re: C4244 conversion from 'double' to 'float' warning

19-Mar-09 7:41

It shouldn't (I made a test).
What is exactly your code (and waht is the error message)?
Smile | :)

penny black19-Mar-09 7:47

Re: C4244 conversion from 'double' to 'float' warning

19-Mar-09 7:47

Here is, what I think, the pertinent part of code:

CString value;
value=mslstr.Mid(parse_start, parse_stop-parse_start);
float htmin;
htmin=static_cast(atof(value));

Here is the error:
.\sruleDoc.cpp(1072) : error C2059: syntax error : '('

Line 1072 is htmin=static_cast(atof(value));

Stuart Dootson19-Mar-09 8:13

Re: C4244 conversion from 'double' to 'float' warning

19-Mar-09 8:13

Should be

htmin=static_cast<float>(atof(value));

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Eytukan19-Mar-09 8:15

Eytukan

19-Mar-09 8:15

lol he mentioned a sample.. to be precise,

static_cast<float>(atof(value))

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

Re: C4244 conversion from 'double' to 'float' warning

Cedric Moonen19-Mar-09 8:32

Cedric Moonen

19-Mar-09 8:32

CPallini wrote:
It shouldn't (I made a test).

But you probably forgot that the < and > characters are removed from your post Wink | ;)

Cédric Moonen
Software developer

Charting control [v1.5]
OpenGL game tutorial in C++

Re: C4244 conversion from 'double' to 'float' warning

CPallini19-Mar-09 8:48

Re: C4244 conversion from 'double' to 'float' warning

19-Mar-09 8:48

Oh, my bad Blush | :O

. Thank you.

CPallini19-Mar-09 8:49

Re: C4244 conversion from 'double' to 'float' warning

19-Mar-09 8:49

Sorry, I made a typo in my example. Fixed now. Sorry again. Blush | :O

Eytukan19-Mar-09 7:28

Eytukan

19-Mar-09 7:28

penny black wrote:
Is only remedy to initialize htmin as double?

Or better would be to ignore it? Roll eyes | :rolleyes:

He never answers anyone who replies to him. I've taken to calling him a retard, which is not fair to retards everywhere.-Christian Graus

Re: C4244 conversion from 'double' to 'float' warning

penny black19-Mar-09 7:37

Re: C4244 conversion from 'double' to 'float' warning

19-Mar-09 7:37

I'd love to. I just migrated some code from VC++6.0 to VS2008 and I'm getting hundreds of C4244 warnings.

Stuart Dootson19-Mar-09 8:11

Re: C4244 conversion from 'double' to 'float' warning

19-Mar-09 8:11

There is, in general, no reason to use float rather than double. 4 bytes memory saved? Big deal. Performance? The math co-processor in Intel apps uses double internally - doubles are actually quicker.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

penny black19-Mar-09 8:55

19-Mar-09 8:55

Thanks for all the info. Looks like I've got two workable solutions.

Message Map Handlers

ForNow19-Mar-09 6:38

ForNow

19-Mar-09 6:38

Hi,

I know MFC has specfic message map macros e.g. ON_WM_CLOSE coreesponding to the

overridable onclose method

However is'nt ON_MESSAGE a catchall

Where I can code the SDK message e.g WM_CLOSE as the first parm and my method to handle this as the second ???

Or if I were handling response from a control (e.g clicking the OK button)

I could code ON_MESSAGE(ID_OK,my_ok_response) to process this message

thnakx

led mike19-Mar-09 7:31

led mike

19-Mar-09 7:31

ForNow wrote:
I could code ON_MESSAGE(ID_OK,my_ok_response) to process this message

Did it work?

Stuart Dootson19-Mar-09 8:25

19-Mar-09 8:25

ForNow wrote:
I could code ON_MESSAGE(ID_OK,my_ok_response) to process this message

No you couldn't - should use ON_COMMAND(ID_OK, my_ok_response) to process that.

ForNow wrote:
Where I can code the SDK message e.g WM_CLOSE as the first parm and my method to handle this as the second ???

use ON_MESSAGE(WM_CLOSE, myCustomCloser) where myCustomCloser has the signature

LRESULT myCustomCloser(WPARAM, LPARAM);

in your window class.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

ForNow19-Mar-09 12:15

ForNow

19-Mar-09 12:15

So ON_MESSAGE is for Windows system messages whereas ON_COMMAND is for anyhting thats WM_USER + .....

thankx

Stuart Dootson19-Mar-09 12:35

19-Mar-09 12:35

ForNow wrote:
So ON_MESSAGE is for Windows system messages

Yes

ForNow wrote:
ON_COMMAND is for anyhting thats WM_USER + .....

No - if you look at the definition of the ON_COMMAND macro, you'll see this:

#define ON_COMMAND(id, memberFxn) \
	{ WM_COMMAND, CN_COMMAND, (WORD)id, (WORD)id, AfxSigCmd_v, \
		static_cast<AFX_PMSG> (memberFxn) },
		// ON_COMMAND(id, OnBar) is the same as
		//   ON_CONTROL(0, id, OnBar) or ON_BN_CLICKED(0, id, OnBar)

What this means is that ON_COMMAND handles the WM_COMMAND[^] message, which (to quote that page) is sent when the user selects a command item from a menu, when a control sends a notification message to its parent window, or when an accelerator keystroke is translated.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

ForNow19-Mar-09 17:05

ForNow

19-Mar-09 17:05

thankx

RegQueryValueEx

siva45519-Mar-09 6:35

siva455

19-Mar-09 6:35

Hi,
Please give me a sample to use RegQueryValueEx()..and i want to store the value in a CString..Please help me out.. as im a beginner..

Re: RegQueryValueEx

CPallini19-Mar-09 7:26

19-Mar-09 7:26

You may find sample code in the RegQueryValueEx documentation page [^].
Smile | :)

Re: RegQueryValueEx

Mattias G19-Mar-09 13:28

Mattias G

19-Mar-09 13:28

Yes, there's a useful sample on that page, if you're interested in getting a data object with an unknown size. But if you want to read a C string and convert that string to a CString, you are probably better off with this:

<br />
BOOL ReadStringFromMysterioiusOSSource(char* destination, int maxChar);<br />
<br />
// ...<br />
<br />
CString myValue;<br />
char buf[438];<br />
ReadStringFromMysterioiusOSSource(buf, 438);<br />
myValue = buf;<br />

(If you really need to use a OS function, just use the CString's assignment operator)

Re: RegQueryValueEx

CPallini19-Mar-09 22:28