acct(4)acct(4)NAMEacct - per-process accounting file format
SYNOPSISDESCRIPTION
Files produced as a result of calling (see acct(2)) have records in the
form defined by whose contents are:
typedef ushort comp_t; /* "floating point":
13-bit fraction, 3-bit exponent */
struct acct {
char ac_flag; /* Accounting flag */
char ac_stat; /* Exit status */
uid_t ac_uid; /* Accounting user ID */
gid_t ac_gid; /* Accounting group ID */
dev_t ac_tty; /* control typewriter */
time_t ac_btime; /* Beginning time */
comp_t ac_utime; /* acctng user time in clock ticks */
comp_t ac_stime; /* acctng system time in clock ticks */
comp_t ac_etime; /* acctng elapsed time in clock ticks */
comp_t ac_mem; /* memory usage in clicks */
comp_t ac_io; /* chars trnsfrd by read/write */
comp_t ac_rw; /* number of block reads/writes */
char ac_comm[8]; /* command name */
};
#define AFORK 01 /* has executed fork, but no exec */
#define ASU 02 /* used super-user privileges */
#define ACCTF 0300 /* record type: 00 = acct */
In the flag is turned on by each and turned off by an (see fork(2) and
exec(2)). The field is inherited from the parent process and is reset
by any Each time the system charges the process with a clock tick, it
also adds to the current process size, computed as follows:
(data size) + (text size) + (number of in-core processes sharing text) +
sum of ((shared memory segment size) / (number of in-core processes attached to segment))
For systems with virtual memory, the text, data, and shared memory
sizes refer to the resident portion of the memory segments. The value
of can be viewed as an approximation to the mean process size, as modi‐
fied by text-sharing.
The structure, which resides with the source files of the accounting
commands, represents the total accounting format used by the various
accounting commands:
WARNINGS
The value for a short-lived command gives little information about the
actual size of the command because can be incremented while a different
command (such as the shell) is being executed by the process.
Kernel internal structures may change from release to release without
warning. Applications directly relying on these structures are not
supported.
Accounting files are currently written in 32-bit format. Thus, 64-bit
applications which read the files need to make special provisions. In
particular, the header declares the field as rather than a in 64-bit
compilations. The field should be cast to in the application before
using it (e.g., in calls to date conversion functions). The accounting
file format will be changed to a 64-bit layout at a future release.
SEE ALSOacct(2), acct(1M), acctcom(1M), exec(2), fork(2).
STANDARDS CONFORMANCEacct(4)
