🚀 go-pugleaf

Re the handling of void * in memchr, etc. Doug Gwyn writes:

>That could be avoided by defining the function as
>	void *memchr(const char *s, int c, unsigned int n)
>which works because of the "same representation" requirement.

I like Doug's suggestion but it did raise another question. 

It's obviously useful to put a prototype in a header and include it
at the site of every call.  However, it's also a good idea to include
it where the function is actually defined.  If one uses Doug's
approach, will the compiler cough or not? For example:


void *memchr(const void *s, int c, unsigned int n);

void *memchr(const char *s, int c, unsigned int n)
{
	/*...*/
}

I tried this on 6 DOS-based compilers all of which CLAIM to be 
either ANSI-conformant or VERY close and they came up 3/3 on whether 
the two function declarations were "compatible" (I'm not sure that's the 
correct term to use here though).

Certainly void * and char * are required to have identical 
representation. However, the two types are different types. Should a 
REAL ANSI C compiler complain or not?

Rex

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Rex Jaeschke     |  Journal of C Language Translation  | C Users Journal
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