Compiling the following code:
#include <vector>
std::vector<int> *factory()
{
std::vector<int> *p = new std::vector<int>;
p->reserve(10);
return p;
}
with -Wall -O -fno-exceptions yields the following error in gcc-4.0.0
and gcc-4.0-20050602:
.../include/c++/4.0.0/bits/vector.tcc: In member function 'void std::vector<_Tp,
_Alloc>::reserve(size_t) [with _Tp = int, _Alloc = std::allocator<int>]':
.../include/c++/4.0.0/bits/vector.tcc:78: warning: control may reach end of
non-void function 'typename _Alloc::pointer std::vector<_Tp,
_Alloc>::_M_allocate_and_copy(size_t, _ForwardIterator, _ForwardIterator) [with
_ForwardIterator = int*, _Tp = int, _Alloc = std::allocator<int>]' being inlined
The warning comes from a catch/rethrow block deep in the bowels of stl
which (because of -fno-exceptions) evaluates to if(false).
This is a false positive warning, which would be fine except
for shops whose policy is to always compile with -Werror -Wall;
there, the warning is fatal. And because this problem is not
confined to just one user source file, it's hard to work around.
This problem does not occur in gcc-3.4.3 nor in recent gcc-4.1 snapshots.
cf. discussion here: http://gcc.gnu.org/ml/libstdc++/2005-06/msg00073.html
--
Summary: [gcc-4.0 regression, rejects-valid]
std::vector.reserve() unusable with -Werror -Wall -O -
fno-exceptions
Product: gcc
Version: 4.0.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: dank at kegel dot com
CC: gcc-bugs at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21951
