const char* to TDesC16

Question

Hi

I have a const char* that specifies the file that I want to delete. I want to use RF::Delete to delete a file which takes a TDesC16 as input argument. Does anyone know how to easily convert

RFs fs;
TUint err;

const char *pFileToDelete = "c:\\myfile.txt";

if ( fs.Connect () == KErrNone )
{
 err = fs.Delete(pFileToDelete); 
 fs.Close();
}

Many thanks,

Answer 1

maybe this will work: http://discussion.forum.nokia.com/forum/showthread.php?t=88018

and http://www.forum.nokia.com/infocenter/index.jsp?topic=/S60%5F5th%5FEdition%5FCpp%5FDevelopers%5FLibrary/GUID-35228542-8C95-4849-A73F-2B4F082F0C44/sdk/doc%5Fsource/guide/Base-subsystem-guide/e32/BuffersAndStrings/Descriptors/DescriptorsGuide3/UsingTDesC16.guide.html

Answer 2

Depends what the character encoding is of the string pFileToDelete. If you don't know, then you need to find out (or define it yourself).

Assuming that it's 7-bit ASCII, then

TPtr8 wrapper(pFileToDelete, User::StringLength(pFileToDelete));
{
    TFileName name;
    name.Copy(wrapper);
    error = fs.Delete(name);
}

Braces are there just because TFileName is quite a large class (512 bytes or so, IIRC), so you want to be slightly wary about putting one on the stack, and give it the smallest scope possible. You could heap-allocate instead.

If it's UTF-8, then there is more work to do, check out ConvertToUnicodeFromUTF8 in class CnvUtfConverter.

It's usually better to define your filename as a descriptor literal in the first place, if you can.

Answer 3

Something along these lines:

_LIT(KMyFilename,"c:\\myfile.txt");
TPtrC filename(KMyFilename);

RFs fs;
TInt err =fs.Connect();
User::LeaveIfError(err);
err = fs.Delete(filename);
...

but check http://descriptors.blogspot.com

Answer 4

RFs fs;
TUint err;
const char *pFileToDelete = "c:\\myfile.txt";
TPtrC8 filename8 = (const TText8*)pFileToDelete;
//ok, so we could use a TBuf or a TFileName, but we'd need to now 
//the size of the TBuf at compile time and 
//TFileNames should never be allocated on the stack due to their size. 
//Easier to use a HBufC.
HBufC* filename = HBufC::NewLC(filename8.Length());
//Copy will only do the right thing if the text in pFiletoDelete is 7-bit ascii
filename->Des().Copy(filename8);
if ( fs.Connect () == KErrNone ){        
    err = fs.Delete(*filename);
    fs.Close();
}
CleanupStack::PopAndDestroy(filename);

I haven't actually compiled this code so it may need som TLC.