open/ close/ read

[Christian Helmuth]

Hello,

On Wed, Feb 07, 2024 at 07:07:05 CET, Nobody III wrote:
> I remember this issue years ago. Basically, the libc read()/write()
> functions didn't loop until they finished reading the number of bytes
> specified. While that behavior may technically meet POSIX standards, it
> isn't standard behavior. Incomplete reads and writes normally only happen
> with special files, e.g. pipes and sockets. I don't remember what changes
> were merged, but it sounds like the solution was only partial. There should
> be a closed GitHub issue about this.

I do not know which "issue" you are referring to but I'm quite aware
that we had repeating discussions about "partial reads". I see words
above as your "opinion" about the matter and in no way "standard".
POSIX and also the ISO C standard are quite explicit about the
problematic nature of read() returning a short count in some cases.
Both standards leave it to the programmer to cope with these
situations and additionally provide a tool for the lazy - fread() [1].
So, if you don't want to treat short/partial reads in your code, just
use fread(), but never spread misleading opinions as universal truth.

[1] https://pubs.opengroup.org/onlinepubs/9699919799/
    "Upon successful completion, fread() shall return the number of
     elements successfully read which is less than nitems only if a
     read error or end-of-file is encountered."

Regards
-- 
Christian Helmuth
Genode Labs

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