获得计算机名，用户名，系统路径，环境路径等。

#include <windows.h>
#include <stdio.h>

#define BUFSIZE 1024

void main()
{
 LPTSTR lpszSystemInfo;      // pointer to system information string
 DWORD cchBuff = BUFSIZE;    // size of computer or user name
 TCHAR tchBuffer[BUFSIZE];   // buffer for string
 
 DWORD dwResult;             // function return value
 
 lpszSystemInfo = tchBuffer;
 
 // Get and display the name of the computer.
 
 if( GetComputerName(lpszSystemInfo, &cchBuff) )
  printf("Computer name:  %s\n", lpszSystemInfo);
 
 // Get and display the user name.
 
 cchBuff = BUFSIZE;
 if( GetUserName(lpszSystemInfo, &cchBuff) )
  printf("User name:  %s\n\n", lpszSystemInfo);
 
 // Get and display the system directory.
 
 if( GetSystemDirectory(lpszSystemInfo, MAX_PATH+1) )
  printf("System directory:  %s\n", lpszSystemInfo);
 
 // Get and display the Windows directory.
 
 if( GetWindowsDirectory(lpszSystemInfo, MAX_PATH+1) )
  printf("Windows directory:  %s\n\n", lpszSystemInfo);
 
 // Display the "environment variables" header.
 
 printf("Environment variables (partial list): \n");
 
 // Expand the OS environment variable.
 
 dwResult = ExpandEnvironmentStrings(
  "OS=%OS%",
  lpszSystemInfo,
  BUFSIZE);
 if( dwResult <= BUFSIZE )
  printf("  %s\n", lpszSystemInfo);
 
 
 // Expand the PATH environment variable.
 
 dwResult = ExpandEnvironmentStrings(
  "PATH=%PATH%",
  lpszSystemInfo,
  BUFSIZE);
 if( dwResult <= BUFSIZE )
  printf("  %s\n", lpszSystemInfo);
 
 // Expand the TMP environment variable.
 
 dwResult = ExpandEnvironmentStrings(
  "TEMP=%TEMP%",
  lpszSystemInfo,
  BUFSIZE);
 if( dwResult <= BUFSIZE )
  printf("  %s\n", lpszSystemInfo);
}