Joshua Hoblitt wrote: > On Sun, Jun 15, 2003 at 09:14:16PM +0300, Jarkko Hietaniemi wrote: > >>>>This just isn't cricket for non-GCC compilers (Solaris, AIX, and Tru64 >>>>claim a syntax error, IRIX seems to tolerate it). That a function >>>>call (Perl_doing_taint in this case) gets expanded to func(a,b,) just >>>>isn't going to work. (What does leaving out an argument like that >>>>_mean_, anyway? An implicit 0?) >>> >>>It is a *macro*, not a function call! Macros operate on strings. An >>>empty string is a perfectly valid string (though I do not know what >> >>When the macro gets expanded at the very beginning of main() we get this: >> >> if (Perl_doing_taint(*&argc, *&argv, )) >> >>which makes many C compilers to choke, but apparently not gcc. >> >> >>>the C standard says on this). >>> >>>Anyway, this slot is not used, so put there NOTUSED. >> >>I have no idea what you mean by NOTUSED. If you mean the trick you said: >> >>#define NOTUSED >>#define MALLOC_CHECK_TAINT2(argc,argv) MALLOC_CHECK_TAINT(argc,argv,NOTUSED) >> >>That doesn't work since that gets expanded to exactly the same as above. > > > A possible solution would be to use __VA_ARGS__. I'm not sure how > portable this is between cpp implementations... it supposedly has worked > with gcc since at least 2.95 (I haven't tried it with anything older > than gcc 3.3) and it is part of C99.
Perl sources are C89 compliant and generally try to stay so (i.e. not introduce C99-isms, at least not unconditionally so). But thanks for the information, that may turn out to be useful for something else. > #define MALLOC_CHECK_TAINT2(argc,...) MALLOC_CHECK_TAINT(argc,__VA_ARGS__) It was two years ago :-) but I think, based on the current perl.h, that we just opted for assuming that the third argument to main while non-standard is at least tolerated widely enough: #define MALLOC_CHECK_TAINT2(argc,argv) MALLOC_CHECK_TAINT(argc,argv,NULL) > > --
