This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 112c. See for the official list.


2711. Source for copy-initializing the exception object

Section: 7.6.18  [expr.throw]     Status: DR     Submitter: Brian Bi     Date: 2023-03-26

[Accepted as a DR at the June, 2023 meeting.]

Neither 14.2 [except.throw] nor 7.6.18 [expr.throw] specifiy the source for copy-initializing the exception object.

Proposed resolution (based on the resolution of issue 2699; approved by CWG 2023-06-12):

  1. Change in 7.6.18 [expr.throw] paragraph 2 as follows:

    Evaluating a throw-expression with an operand throws an exception (14.2 [except.throw]); the type of the exception object is determined by removing any top-level cv-qualifiers from the static type of the operand and adjusting the type from “array of T” or function type T to “pointer to T”. The exception object is copy-initialized (9.4.1 [dcl.init.general]) from the (possibly converted) operand.
  2. Change in 14.2 [except.throw] paragraph 3 as follows:

    Throwing an exception copy-initializes (9.4 [dcl.init], [class.copy.ctor]) a temporary object, called the exception object. If the type of the exception object would be an incomplete type (6.8.1 [basic.types.general]), an abstract class type (11.7.4 [class.abstract]), or a pointer to an incomplete type other than cv void (6.8.4 [basic.compound]), the program is ill-formed.