标题：acct
linux 原文件acct.h
/* Copyright (C) 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#ifndef _SYS_ACCT_H
#define _SYS_ACCT_H 1
#include <features.h>
#define __need_time_t
#include <time.h>
#include <sys/types.h>
__BEGIN_DECLS
#define ACCT_COMM 16
/*
comp_t is a 16-bit "floating" point number with a 3-bit base 8
exponent and a 13-bit fraction. See linux/kernel/acct.c for the
specific encoding system used.
*/
typedef u_int16_t comp_t;
struct acct
{
char ac_flag; /* Accounting flags. */
u_int16_t ac_uid; /* Accounting user ID. */
u_int16_t ac_gid; /* Accounting group ID. */
u_int16_t ac_tty; /* Controlling tty. */
u_int32_t ac_btime; /* Beginning time. */
comp_t ac_utime; /* Accounting user time. */
comp_t ac_stime; /* Accounting system time. */
comp_t ac_etime; /* Accounting elapsed time. */
comp_t ac_mem; /* Accounting average memory usage. */
comp_t ac_io; /* Accounting chars transferred. */
comp_t ac_rw; /* Accounting blocks read or written. */
comp_t ac_minflt; /* Accounting minor pagefaults. */
comp_t ac_majflt; /* Accounting major pagefaults. */
comp_t ac_swaps; /* Accounting number of swaps. */
u_int32_t ac_exitcode; /* Accounting process exitcode. */
char ac_comm[ACCT_COMM+1]; /* Accounting command name. */
char ac_pad[10]; /* Accounting padding bytes. */
};
enum
{
AFORK = 0x01, /* Has executed fork, but no exec. */
ASU = 0x02, /* Used super-user privileges. */
ACORE = 0x08, /* Dumped core. */
AXSIG = 0x10 /* Killed by a signal. */
};
#define AHZ 100
/* Switch process accounting on and off. */
extern int acct (__const char *__filename) __THROW;
__END_DECLS
#endif /* sys/acct.h */
名称:
acct -- 启用/禁止进程信息记录功能
库:
Standard C Library (libc, -lc)
概要:
#include <unistd.h>
int acct(const char * file, int mode);
详述:
acct()系统调用禁止/启用系统记录进程信息。若file为NULL，记录功能将被禁用；
若file指向一个存在的文件（以'\0'结尾），则记录功能被启用，
正常结束的进程都会在该文件尾添加对应的信息。异常结束是指重启或其它致命的系统问题。
acct()不能生成那些永远不会结束的进程的信息。
关于acct()使用的记录结构及其它相关信息，请参阅<sys/acct.h>及acct(5)。
该系统调用只能由超级用户使用。
笔记:
当记录文件所在的文件系统空间已满时，记录功能将被自动禁用；当空间足够时，
它会被自动启用。自动行为可以通过sysctl(8)修改对应的变量来控制：
kern.acct_chkfreq 指定检查剩余空间大小的频率（秒）
kern.acct_resume 剩余空间高于该百分比时，将恢复记录功能
kern.acct_suspend 剩余空间低于该百分比时，将暂停记录功能
返回值:
有错误时返回-1。file文件必须存在且只能由超级用户调用。
错误:
acct()失败时将设置errno为下列错误常量：
[EPERM] 调用者不是超级用户
[ENOTDIR] file中的某目录组分不是目录
[ENAMETOOLONG] file中的某目录组分超过255字节或file超过1023字节
[ENOENT] 文件不存在
[ELOOP] 转换路径时遇到了太多的符号链接
[EACCES] file中某目录组分不允许搜索或file不是一个普通文件
[EROFS] 试图在只读文件系统上请求写操作
[ETXTBSY] 试图对执行中的文件请求写操作
[EFAULT] file参数指向的地址超出了进程的存取空间
[EIO] 读/写文件系统时遇到了I/O错误
历史:
acct()系统调用在AT&T UNIX版本7里首次出现。
（2）ACCT ：ACCOUNT 帐目,帐户 （在外贸中常用到这个缩写）