Some languages do not call the relevant concept "exception handling"; others may not have direct facilities for it, but can still provide means to implement it.
Most assembly languages will have a macro instruction or an interrupt address available for the particular system to intercept events such as illegal op codes, program check, data errors, overflow, divide by zero, and other such.
Digital Equipment Corporation RT11 systems had trap vectors for program errors, i/o interrupts, and such.
Microsoft Windows has specific module calls to trap program errors.
C does not provide direct support to exception handling: it is the programmer's responsibility to prevent errors in the first place and test return values from the functions.
In any case, a possible way to implement exception handling in standard C is to use setjmp/longjmp functions: Two types exist: Example of SEH in C programming language: A try block must have at least one catch or finally clause and at most one finally clause.
prints in analogy with this C++ Another example is In purely functional code, if only one error condition exists, the Maybe type may be sufficient, and is an instance of Haskell's Monad class by default.
For example, event listeners, Promises, and timers can be invoked by the browser at a later point in time and run in an isolated but shared context with the rest of the code.
Observe how the code below will throw a new error every 4 seconds for an indefinite period of time or until the browser/tab/computer is closed.
Another interesting quirk is polymorphism: JavaScript can throw primitive values as errors.
Lastly, note that, as JavaScript uses mark-and-sweep garbage-collection, there is never any memory leakage from throw statements because the browser automatically cleans dead objects—even with circular references.
The forms shown above can sometimes fail if the global variable $@ is changed between when the exception is thrown and when it is checked in the if ($@) statement.
But at the cost of not being able to use return values: Several modules in the Comprehensive Perl Archive Network (CPAN) expand on the basic mechanism: Exception handling is available in PowerBuilder versions 8.0 and above.
The thrown exception is passed as a parameter to the handling block closure, and can be queried, as well as potentially sending #resume to it, to allow execution flow to continue.
Since Tcl 8.6, there is also a try command: [9] Exception handling syntax is very similar to Basic.