When creating scripts and web applications, error handling is an important part. If your code lacks error checking code, your program may look very unprofessional and you may be open to security risks.

This tutorial will teach you how to use the die function.

Basic Error Handling: Using the die() function

The first example shows a simple script that opens a text file:

<?php
        $file=fopen("welcome.txt","r");
?> 

If the file does not exist you might get an error like this:

Warning: fopen(welcome.txt) [function.fopen]: failed to open stream:
No such file or directory in C:\webfolder\test.php on line 2

To avoid that the user gets an error message like the one above, we test if the file exist before we try to access it:

<?php
if(!file_exists("welcome.txt"))
  {
  die("File not found");
  }
else
  {
  $file=fopen("welcome.txt","r");
  }
?> 

Now if the file does not exist you get an error like this:

File not found 

The code above is more efficient than the earlier code, because it uses a simple error handling mechanism to stop the script after the error.

However, simply stopping the script is not always the right way to go. Let’s take a look at alternative PHP functions for handling errors.

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