Basic debugging using logging for iOS apps

2022-01-10 133

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简介： Basic debugging using logging for iOS apps

文章目录

前言
I 、 DEBUG 宏的应用

1.1 发布模式关闭NSLog

II、 NSLog调试技巧

2.1 Where to find NSLog's output
2.2 Improved logging in Objective-C
2.1 Objective-C's boxing capability (`装箱`快速构造数字对象)
2.2 知识补充：装箱和拆箱

see also

Log facility 和level的关系
常见的日志文件
配置【生成/存储日志】策略: `vim /etc/rsyslog.conf`
配置IP

前言

今天周末时间关系，此文只完成了部分内容，后续完整内容请移步到博客（kunnan.blog.csdn.net）

本文demo（请到博客看链接：kunnan.blog.csdn.net）

I 、 DEBUG 宏的应用

应用场景：区分调试模式和发布模式进行特殊处理
自定义preprocessor macro：

The DEBUG preprocessor macro setting in an Xcode project

1.1 发布模式关闭NSLog

//调试模式
#ifdef DEBUG
#define NSLog(...)     NSLog(__VA_ARGS__)
#define KisDebug 1
//#define NSLog(fmt, ...) NSLog((@"[文件名:%s]\n" "[函数名:%s]\n" "[行号:%d] \n" fmt), __FILE__, __FUNCTION__, __LINE__, ##__VA_ARGS__);
#else//发布模式
#define NSLog(...)
#define KisDebug 0
#endif

II、 NSLog调试技巧

2.1 Where to find NSLog’s output

NSLog outputs messages to the Apple System Log facility or to the Console app

2.2 Improved logging in Objective-C

Improved logging in Objective-C

Format specifiers for data types

2.1 Objective-C’s boxing capability (`装箱`快速构造数字对象)

The printf function NSLog offers a number of substitution tokens for printing numbers (%d, %ld, %f, %d, for example). As a convenience, you can use Objective-C’s boxing capability to save time and avoid compiler warnings.

For example

平常也可以使用@ 来快速包装数字类型以对象的形式进行存储和传参

    [discountArray addObject:[[ self class] mj_objectWithKeyValues:@{@"placeholder":QCTLocal(@"please_input_card_num"),@"btnContent":QCTLocal(@"member_see"),@"EnterModelType":@2,@"isEnabled":@1,@"isLast":@1,@"block":block}]];

2.2 知识补充：装箱和拆箱

Java包装类(装箱和拆箱)

全部被final修饰，顺便提一下，java.lang.Math,System,String也被final修饰

包装类是使用面向对象的思想把简单的数据类型封装成类。

1.特点

包装类把简单的数据类型包装成类。

注：简单数据类型不是类，使用简单数据类型主要为了提高代码的运行效率

2.装箱和拆箱

把简单数据类型包装成对应的包装类称为boxing(示例：Integer i=1;将1包装成Integer再使用Object引用Integer对象)

把包装类型转换成简单数据类型称为unboxing（示例：Integer i=1，int p=i;//将包装类Integer转化成简单数据类型int）

注：Integer的拆箱方法为 int intValue()，其他的包装类以此类推

1）包装类都重写了toString方法，equals方法，hashCode方法

2）Integer的API:

String toBinaryString(int i); 将int类型的数据以二进制字符串形式返回

int parseInt(String) 将字符串转化成int类型

int parseInt(Stringstr,int i ) 将字符串转化成对应的进制类型,str为被转换的字符串，i为进制类型（10,8,16）

Integer valueof(String str) 将字符串转换成Integer类型。

Specifier	Description
`%@`	Objective-C object, printed as the string returned by `descriptionWithLocale:` if available, or `description`otherwise. Also works with `CFTypeRef` objects, returning the result of the `CFCopyDescription` function.
`%%`	`'%'` character.
`%d`, `%D`	Signed 32-bit integer (`int`).
`%u`, `%U`	Unsigned 32-bit integer (`unsigned int`).
`%x`	Unsigned 32-bit integer (`unsigned int`), printed in hexadecimal using the digits 0–9 and lowercase a–f.
`%X`	Unsigned 32-bit integer (`unsigned int`), printed in hexadecimal using the digits 0–9 and uppercase A–F.
`%o`, `%O`	Unsigned 32-bit integer (`unsigned int`), printed in octal.
`%f`	64-bit floating-point number (`double`).
`%e`	64-bit floating-point number (`double`), printed in scientific notation using a lowercase e to introduce the exponent.
`%E`	64-bit floating-point number (`double`), printed in scientific notation using an uppercase E to introduce the exponent.
`%g`	64-bit floating-point number (`double`), printed in the style of `%e` if the exponent is less than –4 or greater than or equal to the precision, in the style of `%f` otherwise.
`%G`	64-bit floating-point number (`double`), printed in the style of `%E` if the exponent is less than –4 or greater than or equal to the precision, in the style of `%f` otherwise.
`%c`	8-bit unsigned character (`unsigned char`).
`%C`	16-bit UTF-16 code unit (`unichar`).
`%s`	Null-terminated array of 8-bit unsigned characters. Because the `%s` specifier causes the characters to be interpreted in the system default encoding, the results can be variable, especially with right-to-left languages. For example, with RTL, `%s` inserts direction markers when the characters are not strongly directional. For this reason, it’s best to avoid `%s` and specify encodings explicitly.
`%S`	Null-terminated array of 16-bit UTF-16 code units.
`%p`	Void pointer (`void *`), printed in hexadecimal with the digits 0–9 and lowercase a–f, with a leading `0x`.
`%a`	64-bit floating-point number (`double`), printed in scientific notation with a leading `0x` and one hexadecimal digit before the decimal point using a lowercase `p` to introduce the exponent.
`%A`	64-bit floating-point number (`double`), printed in scientific notation with a leading `0X` and one hexadecimal digit before the decimal point using a uppercase `P` to introduce the exponent.
`%F`	64-bit floating-point number (`double`), printed in decimal notation.

Format specifiers for data types

Type	Format specifier	Considerations
`NSInteger`	`%ld` or `%lx`	Cast the value to `long`.
`NSUInteger`	`%lu` or `%lx`	Cast the value to `unsigned long`.
`CGFloat`	`%f` or `%g`	`%f` works for floats and doubles when formatting; but note the technique described below for scanning.
`CFIndex`	`%ld` or `%lx`	The same as `NSInteger`.
pointer	`%p` or `%zx`	`%p` adds `0x` to the beginning of the output. If you don’t want that, use `%zx` and no typecast.

Basic debugging

Log facility 和level的关系

NSLog outputs messages to the Apple System Log facility or to the Console app

facility：是系统对某种类型事件的定义。

LOG_AUTH

LOG_AUTHPRIV 安全认证

LOG_CRON clock daemon (cron and at) 计划任务事件

LOG_DAEMON 后台进程

LOG_FTP ftp daemon

LOG_KERN kernel messages

LOG_LOCAL0 through LOG_LOCAL7 用户自定义设备

LOG_LPR printer subsystem

LOG_MAIL 邮件系统mail subsystem

LOG_NEWS news subsystem

LOG_SYSLOG syslogd自身产生的日志

LOG_USER (default)

level :指遇到何种情况才记录日志

从下到上，级别从低到高，记录的信息越来越少

LOG_EMERG 紧急，致命，服务无法继续运行，如配置文件丢失

LOG_ALERT 报警，需要立即处理，如磁盘空使用95%

LOG_CRIT 致命行为

LOG_ERR 错误行为

LOG_WARNING 警告信息

LOG_NOTICE 普通，重要的标准信息

LOG_INFO 标准信息

LOG_DEBUG 调试信息，排错所需，一般不建议使用

常见的日志文件

tail /var/log/messages //系统主日志文件

tail -20 /var/log/messages

tail -f /var/log/messages //动态查看日志文件的尾部

tailf /var/log/secure //认证、安全

tail /var/log/maillog //跟邮件postfix相关

tail /var/log/cron //crond、at进程产生的日志

tail /var/log/dmesg //和系统启动相关

tail /var/log/audit/audit.log //系统审计日志

tail /var/log/yum.log //yum

tail /var/log/mysqld.log //MySQL

tail /var/log/xferlog //和访问FTP服务器相关

w //当前登录的用户 /var/log/wtmp

last //最近登录的用户 /var/log/btmp

lastlog //所有用户的登录情况 /var/log/lastlog

配置【生成/存储日志】策略: `vim /etc/rsyslog.conf`

由设备+级别+存放位置组成

FACILITY+LEVEL+FILE组成:

authpriv.* /var/log/secure（SSH信息）

mail.* -/var/log/maillog（发邮件）

cron.* /var/log/cron（创建任务）

authpriv.* * <代表所有终端>
authpriv. @192.168.10.230

authpriv.* @@192.168.10.230

配置IP

/etc/sysconfig/network-scripts/ifcfg-enp2s0中各个参数的意义

vim /etc/sysconfig/network-scripts/ifcfg-enp2s0

NAME=“enp2s0”

DEVICE=“enp2s0”

ONBOOT=yes //是否启用该设备

BOOTPROTO=none //手动(none/static)还是自动(dhcp)

IPADDR=172.16.120.246 //地址

PREFIX=24 //掩码

IPADDR1=192.168.200.246 //额外地址

PREFIX1=24 //额外掩码，注意编号

GATEWAY=172.16.120.254 //网关

DNS1=8.8.8.8 //DNS

DNS2=114.114.114.114 //DNS2

Basic debugging using logging for iOS apps

文章目录

前言

I 、 DEBUG 宏的应用

1.1 发布模式关闭NSLog

II、 NSLog调试技巧

2.1 Where to find NSLog’s output

2.2 Improved logging in Objective-C

2.1 Objective-C’s boxing capability (`装箱`快速构造数字对象)

2.2 知识补充：装箱和拆箱

see also

Log facility 和level的关系

常见的日志文件

配置【生成/存储日志】策略: `vim /etc/rsyslog.conf`

配置IP

热门文章

最新文章

相关电子书

Basic debugging using logging for iOS apps

文章目录

前言

I 、 DEBUG 宏的应用

1.1 发布模式关闭NSLog

II、 NSLog调试技巧

2.1 Where to find NSLog’s output

2.2 Improved logging in Objective-C

2.1 Objective-C’s boxing capability (装箱快速构造数字对象)

2.2 知识补充：装箱和拆箱

see also

Log facility 和level的关系

常见的日志文件

配置【生成/存储日志】策略: vim /etc/rsyslog.conf

配置IP

热门文章

最新文章

相关电子书

2.1 Objective-C’s boxing capability (`装箱`快速构造数字对象)

配置【生成/存储日志】策略: `vim /etc/rsyslog.conf`