How many string types do you guys need?

[skiflyer]

What's with LPWSTR, LPCSTR, LPCTSTR etc?

I want a lousy string...

Actually, in this particular instance I want

ShellExecute(NULL, "open", "C:\\boo\\foo\\yar.exe", NULL, NULL, SW_SHOWNORMAL);

But it says open needs to be a LPWSTR, and the executable path needs to be something else... and that's fine, I can cast them easily, but when I'm looking at example code online no one is doing that, so I was wondering, how are they doing it?

 

[dEVooXiAm]

LPWSTR = WCHAR*
LPCSTR = CONST CHAR*
LPCTSTR = CONST TCHAR*

as you see, they are all pointers to char type (except that WCHAR is 16bit, CHAR is 8bit and TCHAR is either 8bit or 16bit, depending on _UNICODE define.

"open" is 5 8bit characters, so if you're writing a program that uses unicode (16bit) API, you should either use

L"open"

which is a unicode (16bit) string or

_T("open")

which is 8bit or 16bit string depending on _UNICODE define presence.


------------------
When you do it, do it right.

 

[xwb]

You forgot BSTR

 

[dEVooXiAm]

BSTR is mostly for COM usage.
Btw, BSTR = WCHAR*
and it seems it needs additional allocation and deallocation to be used.

------------------
When you do it, do it right.

 

[skiflyer]

I've mostly wedged things into my current project using TEXT()... which I believe is equivalent to L"", but I'm not sure.

saying "open" is a char[4], but still not a LPCSTR because it's not the pointer... right?

What are the people writing examples doing that allows them to not do any of that?

 

[cpjust]

In my version of winnt.h, TEXT(str) is basically just a macro for L"str".

 

[LazyMe]

Btw, BSTR = WCHAR*

BSTR!=WCHAR* :


#if defined(_WIN32) && !defined(OLE2ANSI)
typedef WCHAR OLECHAR;
#else
typedef char OLECHAR;
#endif

typedef OLECHAR* BSTR;


So BSTR is either WCHAR* or char*. Furthermore when used for what it is actually to be used for (COM strings), BSTR!=OLECHAR*, since the BSTR is not necessarily NULL terminated, can contain embedded NULLs and is being preceded by a 4-byte length descripter.

Greetings,
Rick

 

[dEVooXiAm]

What are the people writing examples doing that allows them to not do any of that?

They just use a non-Unicode API. Almost all WinAPI functions that have string parameters have 2 versions - one for 8bit strings, and another for 16bit strings (Unicode).

In my version of winnt.h, TEXT(str) is basically just a macro for L"str"

perform Find Next. TEXT() is same to _T(). The difference is that TEXT() requires UNICODE define, and _T() requires _UNICODE define (note the underscore).

saying "open" is a char[4], but still not a LPCSTR because it's not the pointer... right?

first, "open" is char[5] (it holds terminating null too). LPCSTR is const CHAR*, so it is equivalent to char[5]. Although, you specified that the compiler needed LPWSTR, which is WCHAR*, so you need L"open". If you use TEXT("open") or _T("open"), make sure you have defined either UNICODE or _UNICODE accordingly.

------------------
When you do it, do it right.

 

[cpjust]

perform Find Next. TEXT() is same to _T().

I didn't even find any reference to _T in winnt.h
My TEXT macro is defined like this:

#ifdef  UNICODE                     // r_winnt
...
#  define __TEXT(quote) L##quote    // r_winnt
#else   /* UNICODE */               // r_winnt
...
#  define __TEXT(quote) quote       // r_winnt
#endif /* UNICODE */                // r_winnt
#define TEXT(quote) __TEXT(quote)   // r_winnt

 

[ArkM]

_T macro from <tchar.h>:

Use the _T macro to code literal strings generically, so they compile as Unicode strings under Unicode or as ANSI strings (including MBCS) without Unicode.
...
Tip The _T macro is identical to the _TEXT macro.