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Class object.Exception

The base class of all errors that are safe to catch and handle.

class Exception
  : Throwable ;

In principle, only thrown objects derived from this class are safe to catch inside a catch block. Thrown objects not derived from Exception represent runtime errors that should not be caught, as certain runtime guarantees may not hold, making it unsafe to continue program execution.


this (msg, file, line, nextInChain) Creates a new instance of Exception. The nextInChain parameter is used internally and should always be null when passed by user code. This constructor does not automatically throw the newly-created Exception; the throw statement should be used for that purpose.


file stringThe file name of the D source code corresponding with where the error was thrown from.
info object.Throwable.TraceInfoThe stack trace of where the error happened. This is an opaque object that can either be converted to string, or iterated over with foreach to extract the items in the stack trace (as strings).
line ulongThe line number of the D source code corresponding with where the error was thrown from.
msg stringA message describing the error.


next[get] inout(Throwable)
next[set] ThrowableReplace next in chain with tail. Use chainTogether instead if at all possible.


chainTogether (e1, e2) Append e2 to chain of exceptions that starts with e1.
factory (classname) Create instance of class specified by the fully qualified name classname. The class must either have no constructors or have a default constructor.
message () Get the message describing the error. Base behavior is to return the Throwable.msg field. Override to return some other error message.
opApply (dg) Loop over the chain of Throwables.
opCmp (o) Compare with another Object obj.
opEquals (o) Test whether this is equal to o. The default implementation only compares by identity (using the is operator). Generally, overrides for opEquals should attempt to compare objects by their contents.
refcount ()
toHash () Compute hash function for Object.
toString () Overrides Object.toString and returns the error message. Internally this forwards to the toString overload that takes a sink delegate.
toString () The Throwable hierarchy uses a toString overload that takes a sink delegate to avoid GC allocations, which cannot be performed in certain error situations. Override this toString method to customize the error message.


bool gotCaught;
    throw new Exception("msg");
catch (Exception e)
    gotCaught = true;
    writeln(e.msg); // "msg"


Walter Bright, Sean Kelly


Boost License 1.0.