* [committed] libstdc++: Add static assertions for std::function requirements
@ 2021-08-26 23:13 Jonathan Wakely
0 siblings, 0 replies; only message in thread
From: Jonathan Wakely @ 2021-08-26 23:13 UTC (permalink / raw)
To: libstdc++, gcc-patches
[-- Attachment #1: Type: text/plain, Size: 561 bytes --]
Add static assertions to std::function, so that more user-friendly
diagnostics are given when trying to store a non-copyable target object.
These preconditions were added as "Mandates:" by LWG 2447, but I'm
committing them separately from implementing that, to allow just this
change to be backported more easily.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/bits/std_function.h (function::function(F)): Add
static assertions to check constructibility requirements.
Tested powerpc64le-linux. Committed to trunk.
[-- Attachment #2: patch.txt --]
[-- Type: text/plain, Size: 1516 bytes --]
commit 8cf428bfd3ca967b3d135e311d3e391998a39335
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Thu Aug 26 13:13:27 2021
libstdc++: Add static assertions for std::function requirements
Add static assertions to std::function, so that more user-friendly
diagnostics are given when trying to store a non-copyable target object.
These preconditions were added as "Mandates:" by LWG 2447, but I'm
committing them separately from implementing that, to allow just this
change to be backported more easily.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/bits/std_function.h (function::function(F)): Add
static assertions to check constructibility requirements.
diff --git a/libstdc++-v3/include/bits/std_function.h b/libstdc++-v3/include/bits/std_function.h
index fb86ff1c5f8..e081cd81ef4 100644
--- a/libstdc++-v3/include/bits/std_function.h
+++ b/libstdc++-v3/include/bits/std_function.h
@@ -422,6 +422,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
function(_Functor __f)
: _Function_base()
{
+ static_assert(is_copy_constructible<_Functor>::value,
+ "std::function target must be copy-constructible");
+ static_assert(is_constructible<_Functor, _Functor>::value,
+ "std::function target must be constructible from the "
+ "constructor argument");
+
using _My_handler = _Function_handler<_Res(_ArgTypes...), _Functor>;
if (_My_handler::_M_not_empty_function(__f))
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2021-08-26 23:13 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-08-26 23:13 [committed] libstdc++: Add static assertions for std::function requirements Jonathan Wakely
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).