_inp, _inpw, _inpd

Inputs, from a port, a byte (_inp), a word (_inpw), or a double word (_inpd).

Important note Important

This API cannot be used in applications that execute in the Windows Runtime. For more information, see CRT functions not supported with /ZW.

int _inp( 
   unsigned short port 
unsigned short _inpw( 
   unsigned short port 
unsigned long _inpd( 
   unsigned short port 


I/O port number.

The functions return the byte, word, or double word read from port. There is no error return.

The _inp, _inpw, and _inpd functions read a byte, a word, and a double word, respectively, from the specified input port. The input value can be any unsigned short integer in the range 0 – 65,535.

Because these functions read directly from an I/O port, they might not be used in user code in Windows NT, Windows 2000, Windows XP, and Windows Server 2003.


Required header







For more compatibility information, see Compatibility.


All versions of the C run-time libraries.

Not applicable. To call the standard C function, use PInvoke. For more information, see Platform Invoke Examples.