Problems with IBM RS6000 C compiler

[Stephen J. Friedl]

Hi folks,

     I'm not sure where this really belongs so I tried the
above groups.  There's no RS6000 group, right?

     I am porting some software to the IBM RS6000, and the C
compiler and I are just not getting along.  I am not sure what is
a compiler bug, what is my bug, and what is a misunderstanding
between me and the various standards that this thing is trying to
match.  I'm using the "xlc" invocation of the compiler plus
referring to the 7 Dec 88 draft of the Standard.  For cross-
checking my work, I am using C Issue 5 (ANSI) on the 3B2%.

------

     First, a bug: the following produces a compiler error:

	1 | #ifdef undef
	    .......a....
a - 1506-199: (S) Expecting macro name on #ifdef or #ifndef directive.

I've seen lots of places use this instead of something like
"#if 0", and my reading of section 3.8 of the standard seems
to specifically indicate that this should be OK.

------

Second, I am having problems with prototypes in header files.  It
seems that this compiler is trying to be compliant with ANSI,
POSIX, and X/Open (plus maybe the SVID) and I just don't know
enough about all these standards to know who to blame for this.

For instance, <sys/stat.h> defines the prototype for stat:

	extern int stat(char *filename, struct stat *stptr);

Shouldn't the "filename" argument be const qualified?  I
use const all over my code, and the compiler throws up on
every usage.  The following other functions are mis-prototyped:

<fcntl.h>	open()  creat()
<sys/types.h>	stat()  mkdir()  chmod()  mkfifo()
<sys/pwd.h>	getpwnam()
<sys/grp.h>	getgrnam()

plus probably others.  Is this supposed to be like this?  Why?

------

The last is the one I am least sure of.  What should happen
with the following test program:

	extern void	foo( void *** );

	typedef struct { int a; long b; } any_type;

	any_type	**array;

	main()
	{
		foo(&array);
	}

It complains with:

	9 |         arrsize(&array);
	   .................a.......
a - 1506-193: (S) Function call arg cannot be assigned to corresponding param.

I just don't get it; the ANSI compiler on the 3B2 doen't complain about this.

------

     Anybody have ideas on any of this?  I am stumped and frustrated.


     Oh, a side note.  This is not a flame on the RS6000.  It is
a phenomenally fast machine -- hey, I compare it to the 3B2 --
and it seems to me that IBM has spent a lot of time on it.  They
are early in the cycle so I don't mind finding a few bugs in the
short term.

     Steve

% - I realize that the 3B2 compiler does not define the ANSI standard,
    and I certainly don't believe that a single test is exhaustive, but
    it does provide a brief sanity check.  OK?

-- 
Stephen J. Friedl, KA8CMY / Software Consultant / Tustin, CA / 3B2-kind-of-guy
+1 714 544 6561  / friedl at mtndew.Tustin.CA.US  / {uunet,attmail}!mtndew!friedl

If the ADA bill is so important, why does Congress exempt itself?