C++ GetSystemDirectory()

关于GetSystemDirectory function，参考：https://msdn.microsoft.com/en-us/library/windows/desktop/ms724373(v=vs.85).aspx

以下代码摘自Getting System Information（https://msdn.microsoft.com/en-us/library/windows/desktop/ms724426(v=vs.85).aspx）。

IDE: Microsoft Visual Studio Community 2017 15.5.2

操作系统：Windows 7 x64

 #include "stdafx.h"    /* IDE自行创建的 */
 
 #include <windows.h>
 
 #define INFO_BUFFER_SIZE 21
 
 int main(int argc, char **argv)
 {
     TCHAR infoBuf[INFO_BUFFER_SIZE];
     UINT RetSize;
 
     RetSize = GetSystemDirectory(infoBuf, INFO_BUFFER_SIZE);
 //    RetSize = 0;
     if ((RetSize != ) && (RetSize <= INFO_BUFFER_SIZE)) {
         // If the function succeeds, the return value is the length, in TCHARs, of the string copied to the buffer,
         // not including the terminating null character.
 
         // Display the system directory.
         printf("System Directory: %ls", infoBuf);
     }
     else if (RetSize > INFO_BUFFER_SIZE) {
         // If the length is greater than the size of the buffer,
         // the returnv alue is the size of the buffer required to hold the path,
         // including the terminating null character.
         printf("The size of the buffer is not enough, need %d TCHARs at least. \n", RetSize);
     }
     else {
         // If the function fails, the return value is zero. To get extended error information, call GetLastError.
         printf("Get system directory failed with error: %d", GetLastError());
     }
 
     getchar();
 
     return ;
 }

可以修改INFO_BUFFER_SIZE的值，改变程序的运行结果。

也可以去掉RetSize = 0;前面的注释，模拟错误（实际上不是错误，我只是用来测试if语句的条件）。

不知道是否存在BUG？？？