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From: Markus Wichmann <nullplan@gmx.net>
Newsgroups: gmane.linux.lib.musl.general
Subject: Possible oversight in setvbuf()
Date: Fri, 13 Jul 2018 16:40:52 +0200
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Hi all,

ungetc() seems to depend on f->buf pointing UNGET bytes into a valid
array. fdopen() will provide such a thing. However, setvbuf() will set
f->buf to the very start of the user provided buffer. Bizarrely, UNGET
is deducted from the buffer size, but not added to the pointer.
Oversight or intentional?

Ciao,
Markus