Why return only first character when convert cstring to LPCSTR

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Why Return only First Character when Convert Cstring to LPCSTR

What I have tried:

Dear guy
I'm convert Cstring to LPCSTR with some code below

C++

CString strData1 = L"ABCDE";
LPCSTR spData = (LPCSTR)(LPCTSTR)strData1;
MessageBox(NULL, strData1, L"CString strData", MB_OK);      //=> ABCDE
MessageBox(NULL, (CString)spData, L"LPCSTR spData", MB_OK); //=> A  (What's problem)

Why LPCSTR spData is A (First Character of Cstring strData1)

Posted 27-Jun-17 17:50pm

Mạnh Lê

Updated 14-Apr-23 3:47am

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Comments

Mohibur Rashid 28-Jun-17 0:26am

Casting and converting is not same.
take a look at this https://msdn.microsoft.com/en-us/library/s7wzt4be(v=vs.80).aspx

3 solutions

Solution 1

You cannot use a cast to convert data from one type to another; see WideCharToMultiByte function (Windows)[^]

Posted 27-Jun-17 20:04pm

Richard MacCutchan

Solution 3

one more thing , when you are using function check there should be a function for unicode also..

like in registry there is a function

RegCreateKeyExA

but for Unicode there is another version of same function called

RegCreateKeyExW

Mumtaz Ali

Posted 14-Apr-23 3:47am

Member 11658520

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Jochen Arndt · Accepted Answer · 2017-06-27T21:06:00

As already said you need a conversion instead of a casting. The CString class can do that for you:

// Your code assumes a Unicode build and this example too

CString strData1 = L"ABCDE";

// Create a CStringA. 
// The conversion from Unicode to ANSI is done by the CString class.
// May also use CStringA strData1A(strData1);
CStringA strData1A = strData1;

// Get a LPCSTR from the CStringA
LPCSTR spData = strData1A.GetString();

MessageBox(NULL, strData1.GetString(), L"CString strData", MB_OK);

// Create a CString (CStringW) from a LPCSTR with conversion
MessageBox(NULL, CString(spData).GetString(), L"LPCSTR spData", MB_OK);

You should also avoid using C style castings. Use the C++ casting operators instead (see Type conversions - C++ Tutorials[^] and Casting Operators[^]).