🚀 go-pugleaf

In article <robertl.4.715452734@county.lmt.mn.org>, robertl@county.lmt.mn.org (ROBERT LAUMEYER) writes:
> 
> 	The ANSI C standard seems to have a rather odd mix of file 
> operations.  Why didn't they add (over K&R) some other useful file 
> operations such as fileexist, getfirst, getnext, etc?  It seems that 
> these could not be much more dependent on the underlying file system than 
> rename or remove.

What are getfirst and getnext?  If they are the MS-DOS functions, don't
forget that
(a) wild-cards are very OS-dependent.  (Indeed, not all UNIX shells offer
    the same set of wild-cards.)
(b) When multiple threads may modify the file system (e.g. a multi-user
    system, or a file server accessed by many PCs), it is not altogether
    clear what getnext should do when the file system has _changed_ since
    the original call to getfirst.
(c) there are _other_ file system interfaces, such as the ftw() function,
    with at least as good a claim to standardisation.

Basically, if we had waited for a really good set of file system operations
we'd _still_ be waiting.

As for fileexist, what does that _mean_?  Does a file "exist" for you
if you are not permitted to inspect the directory containing its name?
Even if a file exists, if you are about to run out of file descriptors
or stream buffers you may not be able to open it.

A reasonably good workaround is

	int file_exists(const char *file_name)
	    {
		FILE *stream;
		stream = fopen(file_name, "rb");
		if (stream != NULL) fclose(stream);
		return stream != NULL;
	    }

This at least answers a useful question:  "would I be able to open this file?"
-- 
You can lie with statistics ... but not to a statistician.