[TUHS] Another odd comment in V6

Tony Finch dot at dotat.at
Wed Feb 22 19:59:49 AEST 2017


Norman Wilson <norman at oclsc.org> wrote:
>
> Sometime in the latter days of the Research system (somewhere
> between when the 9/e and 10/e manuals were published), I had
> an inspiration about that, and changed things as follows:
>
> When a system call like read is interrupted by a signal:
> -- If no characters have been copied into the user's
> buffer yet, return -1 and set errno to EINTR (as would
> always have been done in Heritage UNIX).
> -- If some data has already been copied out, return the
> number of characters copied.

Weird, I thought what you describe was the traditional behaviour, e.g.

https://www.freebsd.org/cgi/man.cgi?query=read&sektion=2&manpath=4.3BSD+NET%2F2
https://www.freebsd.org/cgi/man.cgi?query=read&sektion=2&manpath=SunOS+4.1.3

both say you only get EINTR if nothing was read. (This detail seems to go
back to the 4.1c manual.) Was this a BSDism?

Tony.
-- 
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