🚀 go-pugleaf

/*
What, exactly, are gcc's rules for assignments between types involving const?

I was under the impression that assignments which strictly reduce write
access (increase "constness") should be accepted without warning, while
assignments which might indirectly grant write access to read-only data
should be flagged.

However, gcc claims that assignment of a (const char **) to a value
of type (char **) is a "pointer mismatch", while the equivalent
code using an explicitly named intermediate pointer compiles without warning.
I don't see how any sneak-path write access is granted, either way.
There must be some other criteria.

Can someone explain this, or state succinctly gcc's algorithm for declaring
pointer mismatches?

-Jim Avera  	jima@netcom.com
*/
int *pi;
int **ppi;
const int *pI;		/*writable ptr to read-only mem*/
const int **ppI;	/*writable ptr to writable ptr to read-only mem*/
void main() {
	pI = pi; ppI = &pI;	/* this is OK */
	         ppI = π	/* but this is "incompatible pointer". (why?) */
	/* the above 2 lines seem completely equivalent */
	         ppI = ppi;	/* and so is thie an "incompatible pointer" */
}