Query about <dirent.h>

[Chuck Karish]

From: karish at forel.stanford.edu (Chuck Karish)

In article <442 at longway.TIC.COM> gwyn at brl.arpa (Doug Gwyn) wrote:
>In article <441 at longway.TIC.COM> Andy Tanenbaum <uunet!cs.vu.nl!ast> writes:
>->	char	d_name[1];
>-What happens when a program allocates a struct dirent in a program?  The
>-compiler will not allocate enough storage and it will crash when used.
>
>That's what happens when programmers assume things that are not promised
>by the standards.

This is spelled out in the rationale (B.5.1.1).

>-Is it legal to add a line
>-#include <limits.h> 
>-in <dirent.h>?
>
>NO.

A citation would be more useful here than this proclamation.

I haven't been able to find anything in the 1003.1 documents that would
prohibit this.

The form of a header is defined by the implementation.  There are many
places in the Standard where it is required that a particular
identifier be available when a particular header is #included, but I
haven't found any that require that identifiers not be visible when the
headers to which they are assigned have not been #included.

Portable application code must #include headers as listed in the
function descriptions in the standard, if only for compatibility
with implementations that don't support ANSI C.  It will be easier
to identify non-portable code under implementations that refrain from
#including, for example, <sys/types.h> in <stat.h>.

	Chuck Karish		karish at mindcraft.com
	(415) 323-9000		karish at forel.stanford.edu

Volume-Number: Volume 17, Number 75