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Section: 23.2.7 [associative.reqmts], 23.2.4 [sequence.reqmts] Status: CD1 Submitter: Andrew Koenig Opened: 1999-03-02 Last modified: 2016-01-28
Priority: Not Prioritized
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Duplicate of: 451
Discussion:
Table 67 (23.1.1) says that container::erase(iterator) returns an iterator. Table 69 (23.1.2) says that in addition to this requirement, associative containers also say that container::erase(iterator) returns void. That's not an addition; it's a change to the requirements, which has the effect of making associative containers fail to meet the requirements for containers.
Proposed resolution:
In 23.2.7 [associative.reqmts], in Table 69 Associative container
requirements, change the return type of a.erase(q) from
void to iterator. Change the
assertion/not/pre/post-condition from "erases the element pointed to
by q" to "erases the element pointed to by q.
Returns an iterator pointing to the element immediately following q
prior to the element being erased. If no such element exists, a.end()
is returned."
In 23.2.7 [associative.reqmts], in Table 69 Associative container
requirements, change the return type of a.erase(q1, q2)
from void to iterator. Change the
assertion/not/pre/post-condition from "erases the elements in the
range [q1, q2)" to "erases the elements in the range [q1,
q2). Returns q2."
In 23.4.3 [map], in the map class synopsis; and
in 23.4.4 [multimap], in the multimap class synopsis; and
in 23.4.6 [set], in the set class synopsis; and
in 23.4.7 [multiset], in the multiset class synopsis:
change the signature of the first erase overload to
iterator erase(iterator position);
and change the signature of the third erase overload to
iterator erase(iterator first, iterator last);
[Pre-Kona: reopened at the request of Howard Hinnant]
[Post-Kona: the LWG agrees the return type should be
iterator, not void. (Alex Stepanov agrees too.)
Matt provided wording.]
[ Sydney: the proposed wording went in the right direction, but it wasn't good enough. We want to return an iterator from the range form of erase as well as the single-iterator form. Also, the wording is slightly different from the wording we have for sequences; there's no good reason for having a difference. Matt provided new wording, (reflected above) which we will review at the next meeting. ]
[ Redmond: formally voted into WP. ]