Typecast bug

[Gabriel Dos Reis]

<zoltan@bendor.com.au> writes:

| On 26 Apr 2006, Gabriel Dos Reis wrote:
| 
| > <zoltan@bendor.com.au> writes:
| >
| > | It is gcc 4.1.0, --target=arm-elf compiled on an Intel platform and
| > | GNU/Linux.
| > |
| > | The following construct:
| > |
| > | void *p;
| > |
| > | 	((char *)p)++;
| > |
| > | makes the compiler to issue an error message, namely
| > | "invalid lvalue in increment"
| > |
| > | The ((char *)p) construct is perfectly valid object, a char pointer which
| > | can be lvalue and rvalue alike. For some reason gcc 4.1.0 (and 4.0.2 as
| > | well) treats ((SOME_TYPE *)p) as if it could not be an lvalue;
| >
| > indeed, it is not; in any ISO C version I know of.
| 
| OK - my bad. Wrote first thought later. Old gcc accepted the construct and
| legacy code broke on the new compiler. My sincere apologies.
| 
| The question, however, remains: (how) can I tell the compiler to treat a
| pointer declared as void *p; as if it was a SOME_TYPE *p pointer without
| introducing temporaries?

You have to use a cast, and the result is not an lvalue.  Period.

Or, use the original pointer SOME_TYPE *p.

-- Gaby