This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 116a. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2024-12-19

2597. Replaceable allocation and deallocation functions in the global module

[Accepted at the July, 2022 meeting.]

Subclause 10.1 [module.unit] paragraph 7 implicitly attaches the replaceable global allocation or deallocation functions to the global module. Now that extern "C++" can be used to introduce declarations in the global module, even when in the purview of a named module, the provision seems superfluous.

Proposed resolution [SUPERSEDED]:

1. Change in 6.7.6.5.1 [basic.stc.dynamic.general] paragraph 2 as follows:

   The library provides default definitions for the global allocation and deallocation functions. Some global allocation and deallocation functions are replaceable (17.6.3 [new.delete]). A C++ program shall provide at most one definition of a replaceable allocation or deallocation function. Any such function definition replaces the default version provided in the library (16.4.5.6 [replacement.functions]). The following allocation and deallocation functions (17.6 [support.dynamic]) are implicitly declared in global scope in each translation unit of a program and are attached to the global module (10.1 [module.unit]).

2. Change in 10.1 [module.unit] bullet 7.2 as follows:

   • If the declaration is ...
   • Otherwise, if the declaration
     • is a replaceable global allocation or deallocation function (17.6.3.2 [new.delete.single], 17.6.3.3 [new.delete.array]), or
     • is a namespace-definition with external linkage, or
     • appears within a linkage-specification (9.11 [dcl.link]),
     it is attached to the global module.
   • Otherwise, ...

Additional notes (June, 2022):

Forwarded to EWG with paper issue 1273, by decision of the CWG chair.

Approved by EWG telecon 2022-07-07.

Proposed resolution (approved by CWG 2022-07-15):

1. Change in 6.7.6.5.1 [basic.stc.dynamic.general] paragraph 2 as follows:

   The library provides default definitions for the global allocation and deallocation functions. Some global allocation and deallocation functions are replaceable (17.6.3 [new.delete]) ; these are attached to the global module 10.1 [module.unit]). A C++ program shall provide at most one definition of a replaceable allocation or deallocation function. Any such function definition replaces the default version provided in the library (16.4.5.6 [replacement.functions]). The following allocation and deallocation functions (17.6 [support.dynamic]) are implicitly declared in global scope in each translation unit of a program.

2. Change in 10.1 [module.unit] bullet 7.2 as follows:

   • If the declaration is ...
   • Otherwise, if the declaration
     • is a replaceable global allocation or deallocation function (17.6.3.2 [new.delete.single], 17.6.3.3 [new.delete.array]), or
     • is a namespace-definition with external linkage, or
     • appears within a linkage-specification (9.11 [dcl.link]),
     it is attached to the global module.
   • Otherwise, ...