end of file on Mac OS X

I've noticed that yyinput()/input() returns 0 rather than EOF when it 
hits the end of the file. On Linux the expected EOF is returned.

Mac OS X:

ape:Mixfix eker$ flex --version
flex 2.5.35 Apple(flex-31)

Linux:

psi:Mixfix > flex --version
flex 2.5.35

If I examine the C/C++ code generated, there is indeed a difference at 
the relevant line in yyinput()/input():

Mac:

                                 case EOB_ACT_END_OF_FILE:
                                         {
                                         if ( yywrap( ) )
                                                 return 0;

                                         if ( ! 
(yy_did_buffer_switch_on_eof) )
                                                 YY_NEW_FILE;
#ifdef __cplusplus
                                         return yyinput();
#else
                                         return input();
#endif
                                         }

Linux:

                                 case EOB_ACT_END_OF_FILE:
                                         {
                                         if ( yywrap( ) )
                                                 return EOF;

                                         if ( ! 
(yy_did_buffer_switch_on_eof) )
                                                 YY_NEW_FILE;
#ifdef __cplusplus
                                         return yyinput();
#else
                                         return input();
#endif
                                         }

So is this a bug (in the Mac version) or is this weirdness documented 
somewhere?

Steven Eker
http://www.csl.sri.com/people/eker/