setlocale function
Function prototype: char * setlocale (int category, const char * locale);
setlocale located in the header file 
, setlocale () function may be used to program the current area settings (setting local, regional settings), can also be used to obtain the current program area setting information , requires two parameters of setlocale
The first parameter category:
Used to set the scope of the geographical setting. Geographical settings contain the contents of multiple aspects of date formats, number formats, currency formats, character handling, compare, and so on, the current regional settings may affect only certain aspects of the content, it can also affect all content,
Not just the value of the category set, the macro must <locale.h> defined
The second parameter locale:
setlocale function return values:
If setlocale () performed successfully , then returns a pointer to a string, the string contains the name of the current local settings. In other words, setlocale () will return the name of the current regional settings
If setlocale () execution failed (e.g. locale is designated name does not exist, will lead to failure area disposed), then it returns NULL pointer
If no other parameters and other regions with setlocale function program, then the program runs locale C is initialized to the default locale, which uses character codes are all part of the common local ANSI character set encoding is used to write the C language source code the minimum character set,
Setlocale below with reference to geographical settings currently in use give
char *p;
p = setlocale(LC_ALL, NULL);
printf("%s\n", p);
operation result:
From the above you can see the current regional settings used by the compiler is C, if you want to output Chinese characters with a wide, but still there will be problems with the default regional settings (C), the following setlocale try to resolve the wide-character output of Chinese problem
wchar_t SS [ 20 is ];
char * P;
P = the setlocale (the LC_ALL, NULL);
SS [ 0 ] = _T ( ' in ' );
SS [ . 1 ] = _T ( ' text ' );
SS [ 2 ] = _T ( ' \ 0 ' );
the wprintf (L " % LS \ n- " , SS);
the printf ( " Regional settings:% S \ n- " , P);
operation result:
From the above results it can be seen running 'the' text 'word was not correct output, because the default locale is initialized to C, which is the character encoding used for all local public portion ANSI character set encoding is C language source code for writing the smallest character set , the area below with reference to setlocale to Simplified Chinese, the modified code as follows:
wchar_t ss[20];
char *p;
p = setlocale(LC_ALL, "");
ss[0] = _T('中');
ss[1] = _T('文');
ss[2] = _T('\0');
wprintf(L"%ls\n", ss);
printf("地域设置：%s\n", p);
operation result:
Because the operating system is the Chinese environment, so the above code 
can be changed to 
the effect is the same