Re: C and Unix APIs [was: [PATCH] Improve mutt's random data generator.]

On Fri, Apr 24, 2026 at 15:07 +0200, Alejandro Colomar via Mutt-dev wrote:

>> Here's getrandom():
>>
>> ssize_t getrandom(void *buf, size_t buflen, unsigned int flags);
>>
>> The return value is either the number of bytes written into buf, or -1 on
>> error. On error, the global variable errno is set with an error code.
>>
>> Hypothetically, I'd be happier with
>>
>> int getrandom(void *buf, size_t buflen, size_t *n, unsigned int flags);
>
>That complicates things.  It requires writing more code, and also
>complicates static analysis.  Do you initialize 'n' before the call,
>just in case?  Should getrandom(2) assign to 'n' on failure?  If yes,
>what value?

Looks like it cannot return any data with EINTR or any other error, so 
returned length *n would only be valid on success.

>And in the case of integers, it's relatively okay.  If you return
>pointers, you certainly want to return NULL on error, instead of having
>a ** parameter and an int return value for the error.  ** pointers are
>easier to misuse.

That function doesn't return any pointers. There's no **.