Add error handing for bad enivronment and bad parameter

impl/getcomputername.cpp

@@ -1,10 +1,28 @@
 #include "getcomputername.h"
 #include <unistd.h>
 #include <errno.h>
+#include <string>
+#include <langinfo.h>
 
-BOOL GetComputerName(LPTSTR name, LPDWORD len)
+BOOL GetComputerNameW(LPTSTR name, LPDWORD len)
 {
+    const std::string utf8 = "UTF-8";
     errno = 0;
+    
+    // Check parameters
+    if (!name || !len) {
+        errno = ERROR_INVALID_PARAMETER;
+        return 0;
+    }
+    
+    // Select locale from environment
+    setlocale(LC_ALL, "");
+    // Check that locale is UTF-8
+    if (nl_langinfo(CODESET) != utf8) {
+        errno = ERROR_BAD_ENVIRONMENT;
+        return 0;
+    }
+    
     size_t len2 = *len; 
     int host =  gethostname(name, len2);
     if(host == 0)
@@ -17,3 +35,4 @@ BOOL GetComputerName(LPTSTR name, LPDWORD len)
         return FALSE;
     }
 }
+