GetEnvironmentVariable

GetEnvironmentVariable函数从调用该函数的进程的环境变量中,返回指定的变量名的值,该值是一个以零结尾的字符串指针.

DWORD GetEnvironmentVariable(
  LPCTSTR lpName,  // address of environment variable name
  LPTSTR lpBuffer, // address of buffer for variable value
  DWORD nSize      // size of buffer, in characters
);

参数:
lpName:要获取值的变量名字符串指针.
lpBuffer:接收变量值的字符串指针
nSize:接收变量值的内存大小.

返回值:
如果函数成功执行,则返回值是写入字符缓冲区的字符数量,但不包含'\0'字符.
如果没有找到所指的变量,则返回零.
如果字符缓冲区的大小小于变量值的长度,返回值为缓冲区的大小.

速查:
Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Unsupported.
  Header: Declared in winbase.h.
  Import Library: Use kernel32.lib.
  Unicode: Implemented as Unicode and ANSI versions on Windows NT.

另请参阅:
Processes and Threads Overview, Process and Thread Functions, GetEnvironmentStrings, SetEnvironmentVariable