Question: What kind of performance implications are there to consider when using try-catch statements in php 5? 

I've read some old and seemingly conflicting information on this subject on the web before. A lot of the framework I currently have to work with was created on php 4 and lacks many of the niceties of php 5. So, I don't have much experience myself in using try-catchs with php.

Answer: 
Sorry to post to a very old message, but I read the comments and I somewhat disagree, the difference might be minimal with simple piece of codes, or it could be neglectable where the Try/Catch are used for specific parts of code that are not always predictable, but I also believe (not tested) that a simple:

```
if(isset($var) && is_array($var)){
    foreach($var as $k=>$v){
         $var[$k] = $v+1;
    }
}

```

is faster than

```
try{
    foreach($var as $k=>$v){
        $var[$k] = $v+1;
    }
}catch(Exception($e)){
}

```

I also believe (not tested) that a:

```
<?php
//beginning code
try{
    //some more code
    foreach($var as $k=>$v){
        $var[$k] = $v+1;
    }
    //more code
}catch(Exception($e)){
}
//output everything
?>

```

is more expensive than have extra IFs in the code
Generally speaking, they're expensive and not worthwhile in PHP.

Since it is a checked expressions language, you MUST catch anything that throws an exception.

When dealing with legacy code that doesn't throw, and new code that does, it only leads to confusion.

Good luck!