Re: questions - calling matheval() for printf

[Peter Stephenson <pws@xxxxxxx>]

Sorry I didn't reply to this (the bits Bart didn'g) earlier...

Oliver Kiddle wrote:
> argument	stdout		stderr
> 5a		5		printf: "5a" not completely converted
> 
> In the first case, the different error message doesn't worry me but
> math evaluation doesn't return `5'. It is conceivable that someone
> relies on this in a script, passing a string starting with a number and
> redirecting stderr. I could successively chop characters off the right
> of the string until matheval returns without an error. This would need
> a hack to avoid repeated error messages from matheval(). Any other,
> perhaps better suggestions?

If we need this, it would be better to hack matheval to give it an option
to stop and return a pointer to the end, just like strtol().  But I don't
think we need to adhere to POSIX printf semantics that closely.  I'd be
more interested in what other shells do.

> Is there any way I can find out when arithmetic overflows have occurred
> for the second and third cases? matheval() just allows the numbers to
> wrap?

Again, this would be more work and I'm not sure it's worth it in a shell.

> Can a 64-bit integer be something other than long long? It seems I only
> have ZSH_64_BIT_TYPE to check and it might need a different format
> specifier for printf(3) if this is something other than long long.

On Alpha, it will normally be long rather than long long.  However, I
compiled sizeof(long long) with gcc on the Alpha at Sourceforge, and that
seems to be 64-bit too.  I don't think it's a good idea to rely on that,
though --- there's no standard for such things.

Can we make %q do just the same as what ${(q)foo} would do?

-- 
Peter Stephenson <pws@xxxxxxx>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 392070


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