Query about multiple inclusion of a header

[Jeffrey Kegler]

From: jeffrey at algor2.algorists.com (Jeffrey Kegler)

In article <436 at longway.TIC.COM> Andy Tanenbaum <uunet!cs.vu.nl!ast> writes:
>From: Andy Tanenbaum <uunet!cs.vu.nl!ast>
>
>The ANSI C standard specifically states that it is legal for an
>application program to include the ANSI headers (e.g., <limits.h>)
>multiple times in a program.
>
>What about the POSIX headers that are not in the ANSI std, such as
><unistd.h> and <sys/wait.h>.  Is an implementation required to behave
>correctly if they are included multiple times?  If so, could somebody
>point out the section in P1003.1 where this is stated.

>From 2.8.1 of 1003.1: "Additionally, the C Standard requires that it
be possible to include a header more than once, and that a symbol may
be defined in more than one header.  This requirement is also made of
headers for this standard."  This seems to say yes in answer to the
above question.
-- 

Jeffrey Kegler, Independent UNIX Consultant, Algorists, Inc.
jeffrey at algor2.ALGORISTS.COM or uunet!algor2!jeffrey
1762 Wainwright DR, Reston VA 22090

Volume-Number: Volume 17, Number 68