Multi-byte and Unicode

Coding knowledge

A, Unicode multibyte

(. 1) the Windows in , also called Unicode wide multibyte also called narrow byte; VS default use Unicode encoding , in the configuration attribute item attributes >> >> conventional character sets selectable Unicode characters multi-byte character set or sets

(2) Unicode version of the function and multi-byte character string type distinction

Most parameters have a string of the Win32 API functions have two versions

Ending with A, on behalf of multi-byte version	Ending in W, on behalf of the Unicode version	Depending on the version automatically selected
Such as: CreateEventA	Such as: CreateEventW	Such as: CreateEvent

C runtime library also has many similar functions

Multi-byte version	Unicode version	Adaptive version
strcpy	wcscpy	_tcscpy
strcat	wcscat	_tscscat
strlen	wcslen	_tcslen

There are two functions, so there are two characters

Multi-byte characters	Unicode character	Adaptive character
char	wchar_t	TCHAR

(3) common Win32 string type

LPSTR、LPWSTR、LPTSTR、LPCTSTR

LP prefix representative pointer; suffix string representing the STR

LPSTR: on behalf of multi-byte

LPWSTR: on behalf of Unicode

LPTSTR: T adaptive

LPCTSTR: C Representative Representative adaptive const + T

NOTE: Use the variable type, such as an adaptive type LPTSTR, associated strings need to use the TEXT () wrapped

    const char* str = "hello";
    const wchar_t*  wstr = L"hello";
    const TCHAR* tstr = TEXT("hello");

(4) on _T ()

        #ifdef _UNICODE 
        #define _T(X) L ## X   //Unicode版本
        #endif

        #ifndef _UNICODE
        #define _T(X) X     //多字节版本
        #endif

(5) Unicode multibyte selection

1.Unicode program environmental adaptability, will not be garbled problem

2.Unicode program runs faster than the multi-byte program. Cause: An internal Windows are encoded using Unicode, multi-byte function parameters will be handed over to Unicode function after transcoding

3. Background may be multi-byte control, GUI program is preferable to use Unicode