问题
What does the "T" represents in a string. For example _T("Hello").I have seen this in projects where unicode support is needed.What it actually tells the processor
回答1:
_T stands for “text”. It will turn your literal into a Unicode wide character literal if and only if you are compiling your sources with Unicode support. See http://msdn.microsoft.com/en-us/library/c426s321.aspx.
回答2:
From MSDN:
Use the
_Tmacro to code literal strings generically, so they compile as Unicode strings under Unicode or as ANSI strings (including MBCS) without Unicode
回答3:
It's actually used for projects where Unicode and ANSI support is required. It tells the compiler to compile the string literal as either Unicode or ANSI depending on the value of a precompiler define.
Why you would want to do this is another matter. If you want to support Unicode by itself then just write Unicode, in this case L"Hello". The _T() macro was added when you needed to support Windows NT and later (which support Unicode) and Windows 9x/ME (which do not). These days any code using these macros is obsolete, since all modern Windows versions are Unicode-based.
回答4:
It stands for TEXT. You can peek the definition when using IDE tools:
#define _TEXT(x) __T(x)
But I would like to memorize it as "Transformable", or "swi-T-ch":
L"Hello" //change "Hello" string into UNICODE mode, in any case;
_T("Hello") //if defined UNICODE, change "Hello" into UNICODE; otherwise, keep it in ANSI.
来源：https://stackoverflow.com/questions/15498070/what-does-t-stands-for-in-a-cstring