Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!umich!samsung!brutus.cs.uiuc.edu!apple!longway!std-unix
From: karl@IMA.IMA.ISC.COM (Karl Heuer)
Newsgroups: comp.std.unix
Subject: headers and reserved symbols
Message-ID: <520@longway.TIC.COM>
Date: 31 Jan 90 18:27:30 GMT
Sender: std-unix@longway.TIC.COM
Reply-To: karl@IMA.IMA.ISC.COM (Karl Heuer)
Organization: Interactive Systems, Cambridge, MA 02138-5302
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From: karl@IMA.IMA.ISC.COM (Karl Heuer)

In ANSI C, several symbols are reserved only when their associated header is
included.  For example, if a program does not use <stdlib.h>, then it could
use the symbol EXIT_SUCCESS as a local variable and still be strictly
conforming.  (Hence, the implementation must not have one header include
another.)

Is this also true of POSIX?  I thought 1003.1 used pretty much the same
namespace rules as X3J11, but I can't find an explicit guarantee in the Green
Book.  In particular, given that <sys/types.h> reserves the entire *_t
namespace, is it safe for an application to create such a typedef in a module
that does not require that header?

Karl W. Z. Heuer (karl@haddock.isc.com or ima!haddock!karl), The Walking Lint

Volume-Number: Volume 18, Number 33