宽字符wchar_t.
那就要和char来比较：
The char specifier is an integral type.
A char has enough storage to represent a character from the basic character set. The amount of storage allocated for a char is implementation-dependent.
You initialize a variable of type char with a character literal (consisting of one character) or with an expression that evaluates to an integer.
Use signed char or unsigned char to declare numeric variables that occupy a single byte.
当我们声明wchar_t
The wchar_t type specifier is an integral type that has enough storage to represent a wide character literal. (A wide character literal is a character literal that is prefixed with the letter L, for example L'x')。
character literal 这个词用的很好，加L代表这个literal是宽字符。
至于宽字符在内存中的存储，各个编译器可能不同，写个c语言自己看一下吧。