From mboxrd@z Thu Jan  1 00:00:00 1970
To: 9fans@9fans.net
Date: Thu, 10 Sep 2009 09:29:22 +0000
From: comeau@panix.com (Greg Comeau)
Message-ID: <h88ik0$qf9$1@panix3.panix.com>
References: <1d5d51400909090803n4c4d5b7ewba9dfe0573d02495@mail.gmail.com>
Subject: Re: [9fans] porting help please (gcc void pointer handling)
Topicbox-Message-UUID: 6c14dbe8-ead5-11e9-9d60-3106f5b1d025

In article <1d5d51400909090803n4c4d5b7ewba9dfe0573d02495@mail.gmail.com>,
Fernan Bolando <fernanbolando@mailc.net> wrote:
>On Wed, Sep 9, 2009 at 4:36 PM, Greg Comeau<comeau@panix.com> wrote:
>> In article <1d5d51400909080844q1bee4c3s114ccc5e51ce52f5@mail.gmail.com>,
>> Fernan Bolando <fernanbolando@mailc.net> wrote:
>>>...error: initializer is not a constant: F0_Prelude_46primLeave
>>>--h file ---
>>>#define VAP_TAG =A01
>>>#define WORDSHIFT =A05
>>>#define WORDSIZE =A0 (1<<WORDSHIFT)
>>>#define WORDMASK =A0 (WORDSIZE-1)
>>>#define NS =A0 =A0 =A0 =A0 (WORDSIZE>>3)
>>>#define ZAP_BIT =A0 =A0(1L<<(WORDSIZE-1))
>>>-- c file ----
>>>unsigned F0_Prelude_46primLeave[] =3D {
>>> =A0CAPTAG(FN_Prelude_46primLeave,1)
>>>#ifdef PROFILE
>>>, useLabel(PROF_primLeave)
>>>, 0
>>>, 0
>>>, 0
>>>#endif
>>
>> The initializers to some things need to be constants.
>> In your case, it appears that either CAPTAG or useLabel (or both)
>> have ended up not being #define'd. =A0Probably the header they are
>> #define'd in is not being #include'd (you don't show it above,
>> but then you don't show enough of your code to even reproduce it).
>>
>> On a relate note, you can see the results of preprocessing
>> from pcc by using the -E and/or -P options, that way you
>> can see whether the macro ended up getting substituted
>> and what it was substituted to -- or not in your case.
>> Some compilers also have options which will emit the trail of
>> files #include'd but I don't see that option for pcc.
>
>gcc happily compiles a definition like
>#define CT_v249	((void*)startLabel+464)
>
>is it valid just to add to make the porting non-destructive?
>
>#ifdef Plan9
>#define void unsigned char
>#endif

It could be however, two issues:
1) I don't see how this has anything to do with the original problem
   (so I assume it doesn't).
2) There are other uses of void where doing that may not be what you
   want it to be:

    void foo(void);

becomes:

   unsigned char foo(unsigned char);

doubtful this is your intent for either the argument list or
return value.

However, it may or may not make sense for you to typedef a type
that is either void * or char *.  You don't make it clear what
problem is being solved by your question though, so it's unclear
if offering these ideas are just solutions looking for (non)problems
or not :)

Also, re non-destructive, it's unclear what you mean?
--
Greg Comeau / 4.3.10.1 with C++0xisms now in beta!
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