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From: des@des.no (Dag-Erling =?iso-8859-1?q?Sm=F8rgrav?=)
Date: Thu, 08 Jan 2004 21:14:10 +0100
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Subject: structure padding
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In -STABLE, struct kinfo_proc is currently defined as follows:

struct kinfo_proc {
	struct	proc kp_proc;
	struct	eproc {
                /* ... */
		char	e_login[roundup(MAXLOGNAME, sizeof(long))];
		long	e_spare[2];
	} kp_eproc;
};

I want to add an e_sid field to hold the process's session ID:

struct kinfo_proc {
	struct	proc kp_proc;
	struct	eproc {
                /* ... */
		char	e_login[roundup(MAXLOGNAME, sizeof(long))];
                pid_t   e_sid;
		long	e_spare[1];
	} kp_eproc;
};

However, a pid_t is an int, and sizeof int !=3D sizeof long on Alpha.
I'm not sure what will happen: will alignment rules cause gcc to add
four bytes of padding before e_spare, conserving the size of struct
kinfo_proc, or will struct kinfo_proc shrink by four bytes?

DES
--=20
Dag-Erling Sm=F8rgrav - des@des.no