


Examples of using the register_shutdown_function function to intercept fatal errors in PHP
This article mainly introduces examples of using the register_shutdown_function function to intercept fatal errors in PHP. Friends who need it can refer to it
When we are working on projects, fatal errors occasionally occur due to carelessness. If display_errors is set to off, the user will see a blank page. If it is set to on, the fatal error message will be displayed (of course, normal people will not do this).
Then is there any way for us to intercept fatal errors in advance and feedback them to users in our own custom friendly form? There is a function in PHP called register_shutdown_function that allows us to set another function that can be called when the execution is shut down. That is to say, when our script execution is completed or unexpectedly dies and the PHP execution is about to shut down, this function will is called.
Please see an example below:
Copy the code. The code is as follows:
$flag = false;
Function deal_error(){
global $flag;
if (!$flag){
die("This is a rough question, please try again later");
}
return false;
}
register_shutdown_function("deal_error");
// Will fail due to fatal error
//$obj = new NotExistClass(); //Introducing undefined classes
require('./test.php');
$flag = true;
We set the flag to false at the program entry, and finally set it to true, indicating that the program is executing normally. If the flag is not true at the end, it means it died somewhere in the middle. At this time, register_shutdown_function will be called to output our customized error result.
If the above class is not defined, non-existent files are introduced (require or require_once must be used), etc., it will lead to fatal errors. Of course, if your program is missing a punctuation mark or has an extra special character or something, then there is nothing you can do.

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

在php中,可以使用substr()函数来读取字符串后几个字符,只需要将该函数的第二个参数设置为负值,第三个参数省略即可;语法为“substr(字符串,-n)”,表示读取从字符串结尾处向前数第n个字符开始,直到字符串结尾的全部字符。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

查找方法:1、用strpos(),语法“strpos("字符串值","查找子串")+1”;2、用stripos(),语法“strpos("字符串值","查找子串")+1”。因为字符串是从0开始计数的,因此两个函数获取的位置需要进行加1处理。


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