\x表示16进制。
"\xeb\x2a"表示字符串(character string)，其中字符的ascii码值分别等于\xeb和\x2a。
'\xeb\x2a'是字符常量(character constant),int，值随端序(endian)而定。
An integer character constant has type
int. The value of an integer character
constant containing a single character
that maps to a single-byte execution
character is the numerical value of
the representation of the mapped
character interpreted as an integer.
The value of an integer character
constant containing more than one
character (e.g.,'ab'), or containing a
character or escape sequence that does
not map to a single-byte execution
character, is implementation-defined.
0
