saxat från borland hjälpen (men det är ju likvärdigt):
Syntax
#include <conio.h>
int outp(unsigned portid, int value);
Description
Outputs a byte to a hardware port.
outp is a macro that writes the low byte of value to the output port specified by portid.
If outp is called when conio.h has been included, it will be treated as a macro that expands to inline code. If you don't include conio.h, or if you do include conio.h and #undef the macro outp, you'll get the outp function.