CodeIgniter框架源码学习之系统常量定义文件－－constants.php

文件位置： ./application/config/constants.php

文件内容较少直接上代码，解释

defined('BASEPATH') OR exit('No direct script access allowed');

/*

|--------------------------------------------------------------------------

| Display Debug backtrace

|--------------------------------------------------------------------------

|

| If set to TRUE, a backtrace will be displayed along with php errors. If

| error_reporting is disabled, the backtrace will not display, regardless

| of this setting

| 如果设置成true，debug轨迹（backtrace）将会和php错误一起显示，如果error_reporting是不展示的，则debug轨迹（backtrace）也将不会展示，可以忽略这个设置

|

*/

defined('SHOW_DEBUG_BACKTRACE') OR define('SHOW_DEBUG_BACKTRACE', TRUE);

/*

|--------------------------------------------------------------------------

| File and Directory Modes

|--------------------------------------------------------------------------

|

| These prefs are used when checking and setting modes when working

| with the file system. The defaults are fine on servers with proper

| security, but you may wish (or even need) to change the values in

| certain environments (Apache running a separate process for each

| user, PHP under CGI with Apache suEXEC, etc.). Octal values should

| always be used to set the mode correctly.

| 当文件系统工作的时候检查并配置这些首选项；文件系统运行的时候这些默认的值会适当的增加系统的安全性，但是在php或apache的底层单独的为每各用户开一个进程的时候，使用八进制的值永远是正确的

*/

defined('FILE_READ_MODE') OR define('FILE_READ_MODE', 0644);

defined('FILE_WRITE_MODE') OR define('FILE_WRITE_MODE', 0666);

defined('DIR_READ_MODE') OR define('DIR_READ_MODE', 0755);

defined('DIR_WRITE_MODE') OR define('DIR_WRITE_MODE', 0755);

/*

|--------------------------------------------------------------------------

| File Stream Modes

|--------------------------------------------------------------------------

|

| These modes are used when working with fopen()/popen()

| 文件流模式 当我们使用fopen()/popen()的时候需要这些模式

*/

defined('FOPEN_READ') OR define('FOPEN_READ', 'rb');

defined('FOPEN_READ_WRITE') OR define('FOPEN_READ_WRITE', 'r+b');

defined('FOPEN_WRITE_CREATE_DESTRUCTIVE') OR define('FOPEN_WRITE_CREATE_DESTRUCTIVE', 'wb'); // truncates existing file data, use with care

defined('FOPEN_READ_WRITE_CREATE_DESTRUCTIVE') OR define('FOPEN_READ_WRITE_CREATE_DESTRUCTIVE', 'w+b'); // truncates existing file data, use with care

defined('FOPEN_WRITE_CREATE') OR define('FOPEN_WRITE_CREATE', 'ab');

defined('FOPEN_READ_WRITE_CREATE') OR define('FOPEN_READ_WRITE_CREATE', 'a+b');

defined('FOPEN_WRITE_CREATE_STRICT') OR define('FOPEN_WRITE_CREATE_STRICT', 'xb');

defined('FOPEN_READ_WRITE_CREATE_STRICT') OR define('FOPEN_READ_WRITE_CREATE_STRICT', 'x+b');

/*

|--------------------------------------------------------------------------

| Exit Status Codes

|--------------------------------------------------------------------------

|

| Used to indicate the conditions under which the script is exit()ing.

| While there is no universal standard for error codes, there are some

| broad conventions. Three such conventions are mentioned below, for

| those who wish to make use of them. The CodeIgniter defaults were

| chosen for the least overlap with these conventions, while still

| leaving room for others to be defined in future versions and user

| applications.

| 脚本运行中止状态码

| The three main conventions used for determining exit status codes

| are as follows:

|

| Standard C/C++ Library (stdlibc):

| http://www.gnu.org/software/libc/manual/html_node/Exit-Status.html

| (This link also contains other GNU-specific conventions)

| BSD sysexits.h:

| http://www.gsp.com/cgi-bin/man.cgi?section=3&topic=sysexits

| Bash scripting:

| http://tldp.org/LDP/abs/html/exitcodes.html

|

*/

defined('EXIT_SUCCESS') OR define('EXIT_SUCCESS', 0); // no errors

defined('EXIT_ERROR') OR define('EXIT_ERROR', 1); // generic error

defined('EXIT_CONFIG') OR define('EXIT_CONFIG', 3); // configuration error

defined('EXIT_UNKNOWN_FILE') OR define('EXIT_UNKNOWN_FILE', 4); // file not found

defined('EXIT_UNKNOWN_CLASS') OR define('EXIT_UNKNOWN_CLASS', 5); // unknown class

defined('EXIT_UNKNOWN_METHOD') OR define('EXIT_UNKNOWN_METHOD', 6); // unknown class member

defined('EXIT_USER_INPUT') OR define('EXIT_USER_INPUT', 7); // invalid user input

defined('EXIT_DATABASE') OR define('EXIT_DATABASE', 8); // database error

defined('EXIT__AUTO_MIN') OR define('EXIT__AUTO_MIN', 9); // lowest automatically-assigned error code

defined('EXIT__AUTO_MAX') OR define('EXIT__AUTO_MAX', 125); // highest automatically-assigned error code