linux 下 Linux 下char转换为wchar_t 设置本地为utf-8编码 以及wchar 的输入输出

LInux下使用mbstowcs函数可以将char转化为wchar_t
函数含义：convert a multibyte string to a wide char string
说明：       The behaviour of mbstowcs depends on the LC_CTYPE category of the current locale
返回值：   The  mbstowcs() function returns the number of wide characters that make up the converted part of the wide-char-acter string, not including the terminating null wide character.  If an invalid multibyte sequence  was  encountered, (size_t) -1 is returned.

 #include <string.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <wchar.h>
 #include <locale.h>
 #include <iostream>
 using namespace std;
 // 将char类型转化为wchar // locale: 环境变量的值，mbstowcs依赖此值来判断src的编码方式
11 int ToWchar(char* &src, wchar_t* &dest, const char *locale = "zh_CN.utf8"){
   if (src == NULL) {
     dest = NULL;
     return ;
   }
   //根据环境变量设置locale
   setlocale(LC_CTYPE, locale);
   //得到转化为需要的宽字符大小
   int w_size = mbstowcs(NULL, src, ) + ;
   //w_size=0说明mbstowcs返回值为-1。即在运行过程中遇到了非法字符(很有可能使locale没有设置正确)
   if (w_size == ) {
     dest = NULL;
     return -;
   }
   wcout << "w_size" << w_size << endl;
   dest = new wchar_t[w_size];
   if (!dest) return -;
   int ret = mbstowcs(dest, src, strlen(src)+);
   if (ret <= )return -;   return ;
 }
 int main(){
   char* str = "中国123";
   wchar_t *w_str ;
   ToWchar(str,w_str);
   wcout << w_str[] << "--" << w_str[] << "--" << w_str[];
   delete(w_str);
   return ;
 }

 #include <stdio.h>  

 int main(void){
        int       i_number, result;
        float     f_number;
        char      c_number, str[];
        wchar_t   wc_str, ws_str[];
        printf( "\n\nEnter an int, a float, two chars and two strings\n");
        result = scanf( "%d %f %c %C %s %S", 
                              &i_number, &f_number, &c_number, &wc_str, str, ws_str );
        printf( "\nThe number of fields input is %d\n", 
                               result );
        printf( "The contents are: %d %f %c %C %s %S\n",
                              i_number, f_number, c_number, wc_str, str, ws_str);
        wprintf( L"\n\nEnter an int, a float, two chars and two strings\n");
        result = wscanf( L"%d %f %hc %lc %S %ls", 
                              &i_number, &f_number, &c_number, &wc_str, str, ws_str );
        wprintf( L"\nThe number of fields input is %d\n", 
                               result );
        wprintf( L"The contents are: %d %f %C %c %hs %s\n",
                               i_number, f_number, c_number, wc_str, str, ws_str);
 }