TCHAR [] and LPCTSTR

[mce]

could someone help me on the following?

TCHAR name[50];
CString str="test";

name=(LPCTSTR)str;

The above produce compile error
error C2440: '=' : cannot convert from 'const unsigned short *' to 'unsigned short []' Conversion loses qualifiers
I don't want to use LPCTSTR for name bcos i don't want to allocate memory and delete memory ...
Any good fix for the above?

[poccil]

Declaring a string literal automatically allocates the memory necessary to store. Therefore, you need not create an array of characters tostore the string.

'LPTSTR' and 'LPCTSTR' are just types for arbitrary pointers. No memory is allocated in their use.

Rewrite the code like this.

LPTSTR name;
CString str="test";
name=(LPTSTR)str;

I use the LPCTSTR data type only in function prototypes.

[mce]

yes.. i forgot about one thing just now,

i should be able to do the following

LPTSTR name;
CString str="test";
name=(LPTSTR)str;

but what if i need to do something like this:
where memberStruct has a name data type char[50].
something like this:
MEMBERSTRUCT
{
....
char name[50];
.....

}

GetInfo(LPTSTR name)
{
MemberStruct member;
SomebodyFucntion(&member);
//now i need to return char name[50] back through name, how??


}

[Yves M]

Looks like you are compiling this program in Unicode, so your LPSTR will actually be an array of unsigned shorts (2 bytes) while your char name[50] is just an array of single bytes.

There are two solutions :
1) Convert the Unicode string (the LPSTR) to ANSI
2) use an array of unsigned shorts in your struct MEMBERSTRUCT

I guess what you would like to do is option 2)

[mce]

I am compiling for unicode, yes..
yes i would go for option 2, but what if memberStruct is 3rd party struct.(i couldn;t change anything on that)

[mce]

I just want to be clearer as to what i wanted... in GetInfo(LPCTSTR name) fucntion.

Inside this fucntion, on one hand, i have to use CString to facilitate some string manipulation, like CString::Find, CString::ReverseFind etc.. and return the result back through name easily like this:

name=(LPCTSTR)FoundResult;

On the other hand, i need to call a third party fucntion inside GetInfo, which return a char[50] type to me through MemberStruct as described above.
so i need to return this char[50] result back through LPCTSTR name as well... if you can suggest me using types other that LPTSTR as parameter in GetInfo, then it is fine, just that it must be unicode!

[Sam Hobbs]

Originally posted by poccil
Rewrite the code like this.

LPTSTR name;
CString str="test";
name=(LPTSTR)str;

That is likely to cause problems if "name" is expected to be 50 characters. Doing it that way, "name" will have a pointer to the string in the CString and that string is likely to be less than 50 characters. Also, that pointer will become invalid if the CString reallocates it's buffer. A correct way (not necessarily the only correct way) to rewrite the code I think would be:

TCHAR name[50];
CString str="test";
wcscpy(name, str);

[Sam Hobbs]

So to answer mce's question, I think the following general idea will work:

void GetInfo(LPTSTR name) {
CString str=name;
str=T("Info");    // Replace with your string manipulation and such
wcscpy(name, str);
}

This code assumes that name is 50 characters. However the Unicode part is confusing; I am not sure where it is that you need to convert to/from Unicode. If you still need help then you can ask about how to convert to/from Unicode.

[Yves M]

To convert an ANSI string to Unicode, use

BSTR unicodestr;
unicodestr = SysAllocStringLen(NULL, lstrlenA(ansistr) * 2);
MultiByteToWideChar(CODE_PAGE, 0, ansistr, -1, unicodestr, lstrlenA(ansistr));

To convert Unicode to ANSI, use

char *szString;

szString = (char *) malloc(SysStringLen(unicodestr) + 1);
WideCharToMultiByte(CODE_PAGE, 0, unicodestr, -1, ansistr, SysStringLen(unicodestr), NULL, NULL);