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Hello c++ gurus,

I have some remarks on the Appendix C (Compatibility).
 
------------------------------------------------------------------------
	C.1.1  C++ features available in 1985

	13A pointer to function can be assigned to a void*; _conv.ptr_.

Is it correct ?

4.10  Pointer conversions says:
2	An rvalue of type "pointer to cv T," where T is an object
	type, can be converted  to  an  rvalue of type "pointer to
	cv void."

The function type is not object type.
------------------------------------------------------------------------
	C.1.2  C++ features added since 1985

Did you forgot namespaces in this list ?

========================================================================
Additional differences ISO C/C++:
------------------------------------------------------------------------
In C conversion to pointer types and null pointer constant  may be used
in the constant expression.
In C++ they cannot be used in the context of integral constant expression.

ANSI C	3.4
WP C++	expr.const

Example:

#include <stddef.h>

struct A {
	int a;
	int b;
};

void f()
{
	int i;

	switch (i) {
	case 1:
	case offsetof (struct A, b):
		i--;
	}
}

Here I assume semi-standard definition of offsetof macro.

------------------------------------------------------------------------
In C struct member can have the same name, as struct itself.
In C++ it do not.

Example:

struct a {		// vadid C
	int a;		// invalid C++
};
------------------------------------------------------------------------
According to Extensions to ANSI C A.6.5.4 C compiler may use additional
scope rules for external objects.
There is no such rule in C++.

Of course, this rule is not in the ANSI C itself.

Example1:

void f(void)
{
	extern int a[];
}

void g()
{
	int *pi = a+1;	// Valid C, invalid c++.
}

Example2:

void f(void)
{
	extern void g(void);
}

void h(void)
{
	void (*p)(void) = g;
}

------------------------------------------------------------------------
In C and C++ syntax for empty enum is differnent.
In C enumerator list enclosed in `{}' is not allowed to be empty.
In C++ empty enumerator list is allowed, but '{}'
must be present.

C++ WP	dcl.enum
ANSI C	3.5.2.2

Example:

enum a;			// valid C, invalid C++.
enum {};		// valid C++, invalid C.
------------------------------------------------------------------------

--
Alexander N. Krotoff		krotoff@such.srcc.msu.su
Research Computer Center	tel: +7(095)939-2638
Moscow State University		fax: +7(095)939-4430
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