When should I throw an exception as opposed to return an error in PHP?

I'm working on an API wrapper class, which is the first I've made. For the most part it hasn't been too difficult. Getting to the point where I need to deal with the potential of errors being returned by the API, however confused as to how I should go about dealing with them.

Try-catch-finally and then again a try catch

I have often come across situations like :-

try{ 

     ...

     stmts

     ...

} 

catch(Exception ex) {

     ... 

     stmts

     ... 

} finally {

     connection.close // throws an exception

}

Try-catch exception handling practice for iPhone/Objective-C

Apologies if this question has already been answered somewhere else, but I could not find any decisive answer when searching on it:

Why this null pointer exception when using BufferStrategy with swing timer in Java?

Why might I be getting the following exception with the below code?

Filereader null declarations and appending best practice

I want to optimise my file reader function but am not sure if it is best practice to declare the nulls outside of the try loop. Also, is looping and appending chars to a Stringbuffer considered bad practice? I would like to use the exception handling here, but maybe it is better to use another structure? any advice most welcome, thanks.

Alternative solutions for android.os.NetworkOnMainThreadException

Now I'm solving the

android.os.NetworkOnMainThreadException

I put the connect method into separated thread, but when the thread starts, the start() method doesn't invoke the Run() , - and also using the AsyncTask , the task doesn't invoke the doInBackground() method!

iPhone - How to test allocated objects returned by each memory call?

When writing an app, you always have to write alloc/inits, get autoreleased datas returned by the framework classes, ...

Distinguish new vs existing exceptions

I am creating a PHP application and I want to display the number of times an error has occurred. The problem that I am trying to figure out is if an error has already been reported or if its new using the following values: