Re: [PATCH v3] Replace hard-coded path with one from <paths.h>

[Chris Webb <chris@arachsys.com>]

Jakub Narebski <jnareb@gmail.com> writes:

> All other such variables are described at the top of main Makefile,
> for example:
> 
>   #
>   # Define NO_LIBGEN_H if you don't have libgen.h.
> 
> I think that HAVE_PATHS_H should also have such one-line description.
> By the way it the very first variable with HAVE_* rather than NEEDS_*
> or NO_* name.

To be honest, I used the name suggested to me earlier in the thread without
a great deal of checking to see how consistent it was with existing naming
convention.

Blacklisting OSes with a NO_PATHS_H #define feels like a mistake, as unknown
OSes will fail rather than assuming a safe (if slightly untidy) default. I
got caught out assuming that Windows was sane in this regard, for instance.

To me, NEEDS_PATH_H hints that a system with paths.h would break if it
weren't included, rather than that this is an extra feature available on
this OS. But if NEEDS_* is used elsewhere to enable optional extras on
systems which support them, I agree we should change to NEEDS_PATH_H to be
consistent.

> Why not
> 
>   +#ifdef HAVE_PATHS_H
>   +#include <paths.h>
>   +#endif
>   +#ifndef _PATH_DEFPATH
>   +#define _PATH_DEFPATH "/usr/local/bin:/usr/bin:/bin"
>   +#endif
> 
> This way you are covered if some other header provides _PATH_DEFPATH.

Yes, makes sense, although I think _PATH_DEFPATH is very unlikely to be
provided outside of <paths.h>.

Best wishes,

Chris.