Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!olivea!mintaka!bloom-beacon!eru!hagbard!sunic!mcsun!hp4nl!sci.kun.nl!atcmpe!jc
From: jc@atcmp.nl (Jan Christiaan van Winkel)
Newsgroups: comp.lang.c
Subject: Re: 10 commandments and the NULL pointer?
Message-ID: <681@atcmpe.atcmp.nl>
Date: 8 Nov 90 13:09:50 GMT
References: <2390@krafla.rhi.hi.is>
Organization: AT Computing, Nijmegen, The Netherlands
Lines: 30

From article <2390@krafla.rhi.hi.is>, by einari@rhi.hi.is (Einar Indridason):
# int do_something(int *par1, double *par2, char *par3)
# {
# 	/* do something with those pointers/parameters */
# 	/* return some value to tell how well we did */
# }
# 
# 
# main()
# {
# 	.....
# 
# 	x = do_something(NULL, NULL, NULL);
# 	/* is            ^^^^  ^^^^  ^^^^  this right or should I write: */
# 
# 	x = do_something( (int *)NULL, (double *)NULL, (char *)NULL );
# }
since you used prototypes, you can just as well use
 	x = do_something(0, 0, 0);
because the compiler knows the 0's are used in pointer context; it will
automagically cast the value to the right type. Read the FAQ for more
info on the NULL pointer, there's actually quite a lot to be told about
it.
JC

-- 
___  __  ____________________________________________________________________
   |/  \   Jan Christiaan van Winkel      Tel: +31 80 566880  jc@atcmp.nl
   |       AT Computing   P.O. Box 1428   6501 BK Nijmegen    The Netherlands
__/ \__/ ____________________________________________________________________