PHP: Basic Error Handling: Using the die() function

Wednesday, July 8, 2009

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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