Peter,
thank you.
I read all this carefully, and the link that Charles Mills provided, too,
but I still think that things are different here. The situations described
on that site don't fit exactly to my situation.
The unsigned int in my case is large enough to take the address value
(32 bits vs 31 bits), so there should be no problem with that. The main
problem comes from the fact that PL/1 decided long ago in history that
the BUILTIN function NULL which is a pointer that points nowhere
is implemented as 0xFF000000 instead of 0x00000000 ... which
makes some sense, because access to 0xFF000000 (which is
in fact 0x7F000000) will probably abend 0C4 on read, when
access to 0x00000000 doesn't.
But anyway: if PL/1 callers pass a structure containing pointers to
C, and they initialize the structure simply by assigning the empty
string to it, all pointers will contain NULL(), that is 0xFF000000.
So the C functions receiving such structures have to cope with this.
That's why I would like to check if a pointer contains 0xFF000000.
It should not be that hard ... just because C thinks that there are
no pointers having the high order bit on doesn't mean that other languages
think so, too. After all, C is a language on the mainframe and should
try to work together with other languages that exist on the mainframe ...
or is that a too practical point of view?
Let's see ... maybe we get help from IBM on this ... I had a similar
problem some months ago and got it fixed in the end.
Kind regards
Bernd
Am 28.03.2014 14:05, schrieb Farley, Peter x23353:
And sorry for the typo, that if statement should have read:
if (ppli == (uintptr_t) 0xff000000u)
Not unitptr_t.
Peter
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf
Of Farley, Peter x23353
Sent: Friday, March 28, 2014 9:01 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: Compiler error in z/OS C compiler
Bernd,
ISTM that the url provided by Charles Mills yesterday evening to the
"securecoding.cert.org" site is right on target. The example on that page
about using type uintptr_t would seem to apply exactly to your case. If I were you I
would try the uintptr_t solution using both optimization and no optimization.
If I understand that page correctly, you might want to try the code this way:
/**********************************************************/
/* */
/* PLI/1 NULL () => SYSNULL () */
/* */
/**********************************************************/
static void *pli2_null_to_sysnull (void *ptr)
{
uintptr_t ppli = (uintptr_t) ptr;
if (ppli == (unitptr_t) 0xff000000u)
{
return NULL;
}
else
{
return ptr;
}
}
HTH
Peter
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