Questions about restricted pointers

[Spiros Bousbouras]

In 6.7.3.1 of n1124 we read:

If D appears inside a block and does
not have storage class extern, let B
denote the block. If D appears in the
list of parameter declarations of a
function definition, let B denote the
associated block. Otherwise, let B
denote the block of main (or the
block of whatever function is called
at program startup in a freestanding
environment).

I'm not sure I understand this. If we have in file
scope something like
restrict char *p ;
then what is B ? Is it the block of main() ?

A bit further down we read:

A translator is free to ignore any or all
aliasing implications of uses of restrict.

What might these aliasing implications be ? Can
anyone give me some examples ?

 

[Richard Bos]

In 6.7.3.1 of n1124 we read:

If D appears inside a block and does
not have storage class extern, let B
denote the block. If D appears in the
list of parameter declarations of a
function definition, let B denote the
associated block. Otherwise, let B
denote the block of main (or the
block of whatever function is called
at program startup in a freestanding
environment).

I'm not sure I understand this. If we have in file
scope something like
restrict char *p ;
then what is B ? Is it the block of main() ?

Since file scope falls under "otherwise" (being neither inside a block
nor in a parameter declaration list), yes.

Richard