Re: glibc misc/sys/cdefs.h nonull - typo in comment

[Paul Eggert <eggert@cs.ucla.edu>]

On 2023-10-28 16:50, Jonny Grant wrote:
> Could you give an example of a POSIX API text you refer to that 
> specifies many arguments should not be NULL?

"If an argument to a function has an invalid value (such as a value 
outside the domain of the function, or a pointer outside the address 
space of the program, or a null pointer), the behavior is undefined."

https://pubs.opengroup.org/onlinepubs/9699919799.2018edition/functions/V2_chap02.html#tag_15_01_01

This wording is copied from the C Standard.


The April 2023 working draft of C23 has adjusted the wording to be the 
following, and I expect POSIX to follow suit eventually. Notice the new 
restrictions:

"If an argument to a function has an invalid value (such as a value 
outside the domain of the function, or a pointer outside the address 
space of the program, or a null pointer, or a pointer to non-modifiable 
storage when the corresponding parameter is not const-qualified) or a 
type (after default argument promotion) not expected by a function with 
a variable number of arguments, the behavior is undefined.

"If a function argument is described as being an array, the pointer 
actually passed to the function shall have a value such that all address 
computations and accesses to objects (that would be valid if the pointer 
did point to the first element of such an array) are in fact valid.[210]

"[210] This includes, for example, passing a valid pointer that points 
one-past-the-end of an array along with a size of 0, or using any valid 
pointer with a size of 0."