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Function std.exception.collectExceptionMsg

Catches the exception thrown from the given expression and returns the msg property of that exception. If no exception is thrown, then null is returned. E can be void.

string collectExceptionMsg(T, E) (
  lazy E expression

If an exception is thrown but it has an empty message, then emptyExceptionMsg is returned.

Note that while collectExceptionMsg can be used to collect any Throwable and not just Exceptions, it is generally ill-advised to catch anything that is neither an Exception nor a type derived from Exception. So, do not use collectExceptionMsg to collect non-Exceptions unless you're sure that that's what you really want to do.


T The type of exception to catch.
expression The expression which may throw an exception.


void throwFunc() { throw new Exception("My Message."); }
writeln(collectExceptionMsg(throwFunc())); // "My Message."

void nothrowFunc() {}
assert(collectExceptionMsg(nothrowFunc()) is null);

void throwEmptyFunc() { throw new Exception(""); }
writeln(collectExceptionMsg(throwEmptyFunc())); // emptyExceptionMsg


Andrei Alexandrescu and Jonathan M Davis


Boost License 1.0