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From: tim@proton.amd.com (Tim Olson)
Newsgroups: comp.lang.c,comp.lang.c++
Subject: Re: Pointer arithmetic
Message-ID: <1991Jan5.221508.29232@mozart.amd.com>
Date: 5 Jan 91 22:15:08 GMT
References: <1991Jan5.001607.5915@demott.com>
Sender: usenet@mozart.amd.com (Usenet News)
Reply-To: tim@amd.com (Tim Olson)
Organization: Advanced Micro Devices, Austin, TX
Lines: 29

In article <1991Jan5.001607.5915@demott.com> kdq@demott.COM (Kevin D. Quitt) writes:
|     The actual code is:
| 
| 
| const unsigned char *chars   = "some string"
| unsigned char pass[];
| 
|     c   = strchr( chars, toupper( pass[ i ]) ) - chars + 1;
| 
| 
|     gcc would not accept this no matter what I did.

The problem is the "unsigned" type specifier in the declaration for
chars.  Section 3.5.4.1 (Pointer declarators) states that

	For two pointer types to be compatible, both shall be
	identically qualified and both shall be pointers to
	compatible types.

The function "strchr" is defined to return a type "char *"; it is
not compatible with "chars", which is of type "unsigned char *".  Try
removing the "unsigned" specifier from the declaration for "chars", or
explicitly cast the result of the strchr() function to (unsigned char *).


--
	-- Tim Olson
	Advanced Micro Devices
	(tim@amd.com)