GNU gettext Switch languages

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C

win7 64+VS2008
I wrote a simple gettext test procedures are as follows:

#include <stdio.h> 
#include <locale.h> 
#include "libintl.h" 
#include <windows.h> 
#pragma comment(lib,"libintl.lib") 
#define _(S) gettext(S) 
#define PACKAGE "hello" 
int main(int argc, char **argv) 
{ 
char tmp[51]= {0}; 
int t; 
char path[MAX_PATH]= {0}; 
_snprintf(tmp, 51, "LANG=%s", argv[1]); 
t=putenv(tmp); 
bindtextdomain(PACKAGE, "locale"); 
//bind_textdomain_codeset(PACKAGE,"UTF-8"); 
textdomain(PACKAGE); 
printf(_("Hello!")); 
return 0; 
} 

And then build Hello.Po, translation in the generated Hello.Mo file separately
Placed in the following location：

.\Debug\locale\zh_TW\LC_MESSAGES\hello.mo 
.\Debug\locale\zh_CN\LC_MESSAGES\hello.mo 
.\Debug\locale\ja\LC_MESSAGES\hello.mo 
.\Debug\locale\en_US\LC_MESSAGES\hello.mo 
.\Debug\hello.exe 
.\Debug\libiconv2.dll 
.\Debug\libintl3.dll 

Then you run Hello.exe zh_TW (Hello.exe ja Hello.exe en_US) show all Chinese instead of the appropriate language。\Debug\locale\ja\LC_MESSAGES\hello.mo,.\Debug\locale\en_US\LC_MESSAGES\hello.mo,
.\Debug\locale\zh_TW\LC_MESSAGES\hello.mo
Copy respectively. under \Debug\locale\zh_CN\LC_MESSAGES\ was able to copy the appropriate language is displayed。
Is unable to switch the interface language, toggle the display of all Chinese，why is this？