What are the error types in PHP?

In PHP, errors may occur due to grammatical or logical problems; therefore, PHP errors can be divided into several types. This article will take you through the error types of PHP, I hope it will be helpful to you.

Types of Errors in PHP

There are various types of errors in PHP, but it basically There are four main types of errors. Let's take a look at these four main types of errors:

1. Parsing errors or syntax errors:

This is done by the programmer in the program source code error type. Syntax errors are caught by the compiler. After fixing the syntax errors, the compiler compiles the code and executes it. Parsing errors can result from undisclosed quotes, missing or extra parentheses, unclosed braces, missing semicolons, and more.

Example:

<?php 
$x = "php中文网"; 
y = "www.php.cn"; 
echo $x; 
echo $y; 
?>

Error report:

Explanation: In the above program, the $ symbol is missing in line 3, so it An error message is given.

2. Fatal error:

This is the type of error where the PHP compiler understands the PHP code but it identifies an undeclared function. This means calling a function without a function definition.

Example:

<?php 
function add($x, $y) { 
    $sum = $x + $y; 
    echo "sum = " . $sum; 
} 
$x = 0; 
$y = 20; 
add($x, $y); 
  
diff($x, $y); 
?>

Error:

Explanation: In line 10, the function diff() is called, but the function diff The declaration of () is not defined, so it gives an error.

3. Warning errors:

The main reason for warning errors is missing files, which also means that the PHP function calls the missing files.

Example:

<?php  
header("content-type:text/html;charset=utf-8");
$x = "PHP中文网"; 
include ("header.php"); 
echo $x . "，网址为：www.php.cn"; 
?>

Error:

Description: The program calls an undefined file header.php that is not available, so it An error will occur.

4. Note the error:

It is similar to a warning error, which means that the program contains an error, but it allows the execution of the script.

<?php  
header("content-type:text/html;charset=utf-8");
$x = "PHP中文网"; 
echo $x; 
echo $y; 
?>

Error:

Description: This program uses an undeclared variable $y, so it gives the error message.

Common error constants in PHP

Let’s take a look at the common error constants and their descriptions in PHP:

E_ERROR: Fatal error that causes the script to terminate

E_WARNING: Run-time warning that does not cause the script to terminate

E_PARSE: Compile-time parsing error.

E_NOTICE: Runtime notification due to an error in the code

E_CORE_ERROR: Fatal error occurred during PHP initial startup (installation)

E_CORE_WARNING: Occurred during PHP initial startup WARNING

E_COMPILE_ERROR: Fatal compile-time error with script indicating problem.

E_USER_ERROR: User-generated error message.

E_USER_WARNING: User-generated warning message.

E_USER_NOTICE: User-generated notification message.

E_STRICT: Runtime notification.

E_RECOVERABLE_ERROR: Trapable fatal error indicating a dangerous error

E_DEPRECATED: Runtime notification.

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