Path: utzoo!mnetor!uunet!munnari!moncskermit!moncsbruce!cechew
From: cechew@moncsbruce.oz (Earl Chew)
Newsgroups: comp.os.minix
Subject: Minix Library Reentrancy
Message-ID: <433@moncsbruce.oz>
Date: 2 May 88 06:08:16 GMT
Organization: Comp Sci, Monash Uni, Australia
Lines: 20
Keywords: Minix, Library

Has anyone addressed the problem of reentrancy in the Minix library? I came
across a problem the other day, which I think is due to the Minix library NOT
being reentrant (or perhaps just most of it not being reentrant).

I had a process which called signal(SIGALRM, do_alarm) and then called
alarm(1). Within do_alarm() there is a subsequent call to signal() to reset the
signal handler and a call alarm(1).

The main body of the process goes about and does read(). STRANGE things happen.

I think that the cause of this is that the library sends messages to Minix
using a message structure M which is GLOBAL. read() and friends use this to
summon Minix. So does signal() and alarm()....

Comments?

I've also noticed that atoi() (and a few others, but this one in particular)
uses a static. Why, when automatics would suffice?

						Earl Chew