Apply function attributes (e.g., [[gnu::access()]]) to pointees too

[Alejandro Colomar]

Hi,

I was wondering how we could extend attributes such as gnu::access() to
apply it to pointees too.  Currently, there's no way to specify the
access mode of a pointee.

Let's take for example strsep(3):

With current syntax, this is what we can specify:

	[[gnu::access(read_write, 1)]]
	[[gnu::access(read_only, 2)]]
	[[gnu::nonnull(1, 2)]]
	[[gnu::null_terminated_string_arg(2)]]
	char *
	strsep(char **restrict sp, const char *delim);

I was thinking that with floating numbers, one could specify the number
of dereferences with a number after the decimal point.  It's a bit
weird, since the floating point is interpreted as two separate integer
numbers separated by a '.', but could work.  In this case:

	[[gnu::access(read_write, 1)]]
	[[gnu::access(read_write, 1.1)]]
	[[gnu::access(read_only, 2)]]
	[[gnu::nonnull(1, 2)]]
	[[gnu::null_terminated_string_arg(1.1)]]
	[[gnu::null_terminated_string_arg(2)]]
	char *
	strsep(char **restrict sp, const char *delim);

Which would mark the pointer *sp as read_write and a string.  What do
you think about it?

Cheers,
Alex

-- 
<https://www.alejandro-colomar.es/>
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