Multiple catch blocks in PHP - Step-by-Step Execution

Concept Flow - Multiple catch blocks

Try block starts

↓

Code runs

↓

Exception thrown?

No→Try block ends normally

Yes↓

Check first catch block type

↓

Handle

↓

No matching catch

→Uncaught exception

↓

End try-catch

The try block runs code that might throw exceptions. If an exception occurs, PHP checks each catch block in order to find one matching the exception type to handle it.

Execution Sample

PHP

<?php
try {
  throw new Exception("Error!");
} catch (TypeError $e) {
  echo "Type error caught";
} catch (Exception $e) {
  echo "Exception caught";
}
?>

This code throws an Exception, which is caught by the second catch block and prints a message.

Execution Table

Step	Action	Exception Thrown?	Catch Block Checked	Catch Block Matches?	Output
1	Enter try block	No	N/A	N/A
2	Throw Exception("Error!")	Yes: Exception	catch(TypeError)	No
3	Check next catch block	Yes: Exception	catch(Exception)	Yes	Exception caught
4	Catch block executed	Handled	N/A	N/A	Exception caught
5	Exit try-catch	Handled	N/A	N/A	Exception caught

💡 Exception caught by catch(Exception), so execution continues after try-catch.

Variable Tracker

Variable	Start	After Step 2	After Step 3	Final
$e	undefined	Exception object created	Exception object assigned in catch	Exception object assigned in catch

Key Moments - 2 Insights

Why doesn't the first catch block handle the Exception?

Because the first catch block is for TypeError, but the thrown exception is Exception. The execution_table row 2 shows catch(TypeError) checked and does not match.

What happens if no catch block matches the exception?

The exception remains uncaught and causes a fatal error. The concept_flow shows that if no catch matches, the exception is uncaught.

Visual Quiz - 3 Questions

Look at the execution_table at step 3, which catch block matches the exception?

A catch(TypeError)

B catch(Exception)

C No catch block matches

D Both catch blocks match

💡 Hint

See execution_table row 3 where catch(Exception) matches the thrown Exception.

At which step does the exception get handled?

A Step 4

B Step 3

C Step 2

D Step 5

💡 Hint

Check execution_table row 4 where catch block is executed and output is produced.

If the thrown exception was a TypeError instead, which catch block would handle it?

A catch(Exception)

B No catch block would handle it

C catch(TypeError)

D Both catch blocks would handle it

💡 Hint

Refer to variable_tracker and execution_table row 2 where catch(TypeError) is checked first.

Concept Snapshot

try {
  // code that may throw
} catch (ExceptionType1 $e) {
  // handle ExceptionType1
} catch (ExceptionType2 $e) {
  // handle ExceptionType2
}

PHP checks catch blocks in order and runs the first matching one.

Full Transcript

This example shows how PHP handles multiple catch blocks. The try block runs code that throws an Exception. PHP checks each catch block in order. The first catch block is for TypeError, which does not match. The second catch block matches Exception, so it runs and prints 'Exception caught'. If no catch block matched, the exception would be uncaught and cause an error. Variables like $e hold the exception object inside the catch block. This flow helps handle different error types separately.