outp, outpw, _outp, _outpw, _outpd

Outputs, at a port, a byte (outp, _outp), a word (outpw, _outpw), or a double word (_outpd).

Syntax

int _outp(
   unsigned short port,
   int data_byte
);
unsigned short _outpw(
   unsigned short port,
   unsigned short data_word
);
unsigned long _outpd(
   unsigned short port,
   unsigned long data_word
);

Parameters

port
Port number.

data_byte, data_word
Output values.

Return value

The functions return the data output. There's no error return.

Remarks

The _outp, _outpw, and _outpd functions write a byte, a word, and a double word, respectively, to the specified output port. The port argument can be any unsigned integer in the range 0 - 65,535. data_byte can be any integer in the range 0 - 255. data_word can be any value in the range of an integer, an unsigned short integer, and an unsigned long integer, respectively.

Because these functions write directly to an I/O port, they can't be used in user-mode Windows code.

For information about using I/O ports in the Windows operating system, see Serial communications.

The outp and outpw names are older, deprecated names for the _outp and _outpw functions. For more information, see POSIX function names.

Requirements

For more compatibility information, see Compatibility.

Libraries

All versions of the C run-time libraries.

See also

Console and port I/O
inp, inpw, _inp, _inpw, _inpd