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From: jim@ism780b.UUCP
Newsgroups: net.lang.c
Subject: Re: what about alignment problems? - (nf)
Message-ID: <12@ism780b.UUCP>
Date: Wed, 1-Aug-84 00:31:27 EDT
Article-I.D.: ism780b.12
Posted: Wed Aug  1 00:31:27 1984
Date-Received: Sun, 22-Jul-84 03:04:37 EDT
Lines: 37

#R:watmath:-831800:ism780b:25500006:000:1184
ism780b!jim    Jul 14 12:38:00 1984

Try

struct _aschar   {char    _cchar;   char   _achar;};
struct _asshort  {char    _cshort;  short  _ashort;};
struct _asint    {char    _cint;    int    _aint;};
struct _aslong   {char    _clong;   long   _along;};
struct _asfloat  {char    _cfloat;  float  _afloat;};
struct _asdouble {char    _cdouble; double _adouble;};
struct _asptr    {char    _cptr;    char * _aptr;};
#define QUOTE(x)x
#define alignof(t) ( (int)&((struct QUOTE(_as)t *)0)->QUOTE(_a)t )

main(){
	printf("%d %d %d %d %d %d %d\n",
	    alignof(char), alignof(short), alignof(int), alignof(long),
	    alignof(float), alignof(double), alignof(ptr));
}

Admittedly, ptr is a hack and assumes all pointers have the same alignment
requirement (more likely than that they all have the same size), and it
would be a lot cleaner if alignof were in the language.

While we are at it, what would be even more useful would be typeof,
especially if it could be used in declarations, so you could do

	/* declaration with initialization */
	typeof(foo) foosave = foo;

or

#define acopyof(foo) ( *(typeof(foo) *) \
	memcpy(malloc(sizeof(foo)), (char *)&(foo), sizeof(foo)) )

-- Jim Balter, INTERACTIVE Systems (ima!jim)