# To subscribers of the xforms list from Ivan Powis <Ivan.Powis@nottingham.ac.uk> :
>
> # To subscribers of the xforms list from joel <joel@dabbles-n-doodads.com> :
>
> Actually, I'm looking for an empty string not if a pointer is null. So,
> strcmp(string,"") works fine. I'm not sure why NULL works under
> HPUX. I checked how its defined, and NULL = 0 under both OS's.
> So maybe either the compiler or the implementation of strcmp under
> HPUX views NULL as an empty string? Anyhow, as someone else
> emailed me strcmp(string,"") is really what I meant to do and works
> fine under both OS's.
>
HPUX by default dereferences NULL pointers as you have seen exactly so
that their use does not generate error traps. Thus your use of a NULL
pointer to mean "" works fine on HP although it was surely wrong to
write your particular example this way. This feature is sometimes
"useful" for the non-rigorous programmer eg with a file selector which
may return a null string if cancelled. A strcmp or similar can then
check the returned string without needing to explicitly check for a
null pointer return. I discovered this when porting some xforms apps
from HP to Linux.
Ivan
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___ ___/ _ __ / Ivan Powis [Ivan.Powis@Nottingham.ac.uk]
/ / / School of Chemistry
/ / _/ University of Nottingham
/ ___/ Nottingham NG7 2RD, UK
/ / TEL: +44-115-951-3467
/ / FAX: +44-115-951-3562
_______/ ____/ http://www.chem.nott.ac.uk/IP.html
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