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Try {Import-Module ActiveDirectory} Catch [Exception1] {# Statements that execute in the event of an exception, matching the exception} Catch [Exception2],[Exception3etc] {# Statements that execute in the event of an exception, matching any of the exceptions} Catch {# Statements that execute in the event of an exception, not handled more ...
An exception handling mechanism allows the procedure to raise an exception [2] if this precondition is violated, [1] for example if the procedure has been called on an abnormal set of arguments. The exception handling mechanism then handles the exception. [3] The precondition, and the definition of exception, is subjective.
The scope for exception handlers starts with a marker clause (try or the language's block starter such as begin) and ends in the start of the first handler clause (catch, except, rescue). Several handler clauses can follow, and each can specify which exception types it handles and what name it uses for the exception object.
Exception swallowing can also happen if the exception is handled and rethrown as a different exception, discarding the original exception and all its context. In this C# example, all exceptions are caught regardless of type, and a new generic exception is thrown, keeping only the message of the original exception.
In the Java programming language, the try...catch block is used often to catch exceptions. All potentially dangerous code is placed inside the block and, if an exception occurred, is stopped, or caught.
PHP generally follows C syntax, with exceptions and enhancements for its main use in web development, which makes heavy use of string manipulation. PHP variables must be prefixed by " $ ". This allows PHP to perform string interpolation in double quoted strings, where backslash is supported as an escape character .
In some languages multi-level breaks are also possible. For handling exceptional situations, specialized exception handling constructs were added, such as try/catch/finally in Java. The throw-catch exception handling mechanisms can also be easily abused to create non-transparent control structures, just like goto can be abused. [41]
The statements within the try block are executed, and if any of them throws an exception, execution of the block is discontinued and the exception is handled by the catch block. There may be multiple catch blocks, in which case the first block with an exception variable whose type matches the type of the thrown exception is executed.