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）