Path: utzoo!mnetor!uunet!mcvax!ukc!eagle!icdoc!cam-cl!am
From: am@cl.cam.ac.uk (Alan Mycroft)
Newsgroups: comp.lang.c
Subject: Re: lint diagnostic
Message-ID: <1130@jenny.cl.cam.ac.uk>
Date: 20 Jan 88 18:04:59 GMT
References: <365@osupyr.UUCP> <5304@iuvax.UUCP>
Reply-To: am@cl.cam.ac.uk (Alan Mycroft)
Organization: U of Cambridge Comp Lab, UK
Lines: 34

[The last line is a query as to whether a full lint can be written!]

In article <5304@iuvax.UUCP> bobmon@iuvax.UUCP (Bobmon) writes:
>In article <365@osupyr.UUCP> gae@osupyr.UUCP (Gerald Edgar) writes:
>+defmach(lo) int lo; [...]
>+main()
>+{ printf("sizeof(int) = %d\n",sizeof(int));
>+  printf("sizeof(long) = %d\n",sizeof(long));
>+  defmach(65535);
>+  exit(0); }
[Execution]
>+sizeof(int) = 4; sizeof(long) = 4; 0000ffff
[Lint]
>+defmach, arg. 1 used inconsistently	x.c(6)  ::  x.c(13)

Doug Gwyn says..
>You passed it a long (65535 on a 16-bit machine) but it expects an int.

I think a more correct explaination is that you have a non-matching
cc and lint -- lint thinks sizeof(int) == 2 so that
65535 has type (long int) whereas cc thinks sizeof(int)==4 so that
65535 has type (int).
You can test it by trying something like
  int a[256/(sizeof(int)-2)];
and seeing if lint splutters.

Thus it would seem to be very hard indeed to write a lint which tries
hard to find 'strictly conforming' ANSI programs -- each number above
0x7fff would be regarded as having two or more types:
  E.g. int x = 99999;      is dubious if sizeof(int)==2
whereas
       printf("%ld", 99999) is dubious if sizeof(int)==4
(it may not work if sizeof(long)==8).
Things become even harder with size_t/ptrdiff_t...