ACCT(5)

NAME
acct - execution accounting file

SYNOPSIS
#include <sys/acct.h>

DESCRIPTION
The kernel maintains the following acct information structure for all processes. If a process terminates, and accounting is enabled, the kernel calls the acct(2) function call to prepare and append the record to the accounting file.

    /*
     * Accounting structures; these use a comp_t type which is a 3 bits base 8
     * exponent, 13 bit fraction ``floating point'' number.  Units are 1/AHZ
     * seconds.
     */
    typedef u_short comp_t;
    struct acct {
    	char	ac_comm[10];	/* name of command */
    	comp_t	ac_utime;	/* user time */
    	comp_t	ac_stime;	/* system time */
    	comp_t	ac_etime;	/* elapsed time */
    	time_t	ac_btime;	/* starting time */
    	uid_t	ac_uid;		/* user id */
    	gid_t	ac_gid;		/* group id */
    	short	ac_mem;		/* memory usage average */
    	comp_t	ac_io;		/* count of IO blocks */
    	dev_t	ac_tty;		/* controlling tty */
    #define	AFORK	0x01		/* forked but not execed */
    #define	ASU	0x02		/* used super-user permissions */
    #define	ACOMPAT	0x04		/* used compatibility mode */
    #define	ACORE	0x08		/* dumped core */
    #define	AXSIG	0x10		/* killed by a signal */
    	char	ac_flag;	/* accounting flags */
    };
    /*
     * 1/AHZ is the granularity of the data encoded in the comp_t fields.
     * This is not necessarily equal to hz.
     */
    #define	AHZ	64
    #ifdef KERNEL
    struct vnode	*acctp;
    #endif

If a terminated process was created by an execve(2), the name of the executed file (at most ten characters of it) is saved in the field ac_comm and its status is saved by setting one of more of the following flags in ac_flag: AFORK, ACORE and ASIG.

The ASU and ACOMPAT flags are no longer recorded by the system, but are retained for source compatibility.

SEE ALSO
lastcomm(1), acct(2), execve(2), accton(8), sa(8)

HISTORY
A acct file format appeared in AT&T UNIX.