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Message-ID: <alpine.LRH.2.02.2006261518390.19500@key0.esi.com.au>
Date: Fri, 26 Jun 2020 15:39:51 +1000 (AEST)
From: Damian McGuckin <damianm@....com.au>
To: musl@...ts.openwall.com
Subject: Re: errno not set to EBADF when reading from invalid
descriptor
On Fri, 26 Jun 2020, Markus Wichmann wrote:
> So I can't actually use a FILE open for reading and writing that refers
> to something non-seekable, like a serial line, to both read and write to
> it?
Certainly STDIO allows this, but you need to be very careful. about doing
it.
Years ago, I would send a string down a serial line opened Read/Write, as
an atomic write, and then immediately, sit on the line waiting for a reply
on the same serial line. I was simply trying to retreive the Postscript
handshake between the system and the printer which was a very small number
of characters.
Doing it with 2 FILEs is much smarter for the general case.
Regards - Damian
Pacific Engineering Systems International, 277-279 Broadway, Glebe NSW 2037
Ph:+61-2-8571-0847 .. Fx:+61-2-9692-9623 | unsolicited email not wanted here
Views & opinions here are mine and not those of any past or present employer
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