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     The inp and inpw functions read a byte and a word, respectively,
     from the specified input port. The outp and outpw functions write
     a byte and a word, respectively, to the specified output port.
     These functions are supported in OS/2 protected mode.
 
     The <port> argument can be any unsigned integer in the range
     0-65,535. The <databyte> argument can be any integer in the range
     0-255. The <dataword> argument can be any value in the range
     0-65,535.
 
     You must use a .DEF file to declare the IOSEG segment that the
     run-time library uses to perform input/output on the port. In
     addition, the intrinsic (/Oi) versions of these functions do not
     work unless you put the code in a segment marked with the IOPL
     keyword in the .DEF file.
 
     Since you cannot do IOPL from a regular code segment, the run-time
     library has declared a separate code segment called _IOSEG. In
     order to use any of these functions in any of the protected-mode
     run-time libraries (?LIBCP, LLIBCDLL, LLIBCMT, or CDLLOBJS-based
     DLL), you must have a .DEF file containing the following line:
 
          SEGMENTS _IOSEG CLASS 'IOSEG_CODE' IOPL
 
     Return Value
 
     The inp and inpw functions return the byte or word read from
     <port>. The outp and outpw functions return the data that was
     output. There is no error return.
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