Q36706: Warning C4017 Cast of int Expression to far Pointer

Article: Q36706
Product(s): See article
Version(s): 5.00 5.10 | 5.10
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | s_quickc s_error | mspl13_c
Last Modified: 14-NOV-1988

This information is from section D.1.3 (Page 340) of the "Microsoft
QuickC Programmer's Guide" and section E.3.3 (Page 269) of the
"Microsoft C Optimizing Compiler User's Guide" for Versions 5.00 and
5.10.

This message indicates potential problems but does not hinder
compilation and linking. The number in parentheses at the end of a
warning-message description gives the minimum warning level that must
be set for the message to appear.

The following is the warning:

C4017       cast of int expression to far pointer

            A far pointer represents a full segmented address.  On
            an 8086/8088 processor, casting an 'int' value to a
            far pointer may produce an address with a meaningless
            segment value.  (1)

A possible cause for this warning is that a function that returns a far
pointer was not prototyped and the compiler assumed the return type of
the function to be "int" instead of a far pointer as was actually
intended.

The followin is a code example:

main()
{
  char far *address ;

  address = foo () ;
}

Since foo was not prototyped, the compiler will assume that foo
returns an integer. If the warning level is set at 2, this code would
receive the warning C4016 "foo : no function return type" (if the
warning level were set to 1).

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