[Bug c++/59070] New: Captured object is being moved from the lambda on returning it.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59070
Bug ID: 59070
Summary: Captured object is being moved from the lambda on
returning it.
Product: gcc
Version: 4.8.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: sir_nawaz959 at yahoo dot com
I'm using GCC 4.8.1
Here is the code which reproduces this bug:
std::vectorstd::string items {default};
auto add = [=](std::string item) mutable
{ items.push_back(item); return items; };
std::cout add(one) std::endl;
std::cout add(two) std::endl;
std::cout add(three) std::endl;
Imagine that operator is overloaded for std::vector which all items on ONE
line. The expected out is:
default one
default one two
default one two three
But it actually outputs this:
default one
two
three
So it seems on the first return, the captured vector is moved.
However, if I define the lambda as:
auto add = [=](std::string item) mutable
{ items.push_back(item); auto x = items; return x; } ;
OR as:
auto add = [=](std::string item) mutable
{ auto x= items; x.push_back(item); return x; } ;
It prints the expected output.
[Bug c++/59070] Captured object is being moved from the lambda on returning it.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59070
Sarfaraz Nawaz sir_nawaz959 at yahoo dot com changed:
What|Removed |Added
Status|RESOLVED|NEW
Resolution|WORKSFORME |---
--- Comment #4 from Sarfaraz Nawaz sir_nawaz959 at yahoo dot com ---
Here is the complete testcase which compiles fine but gives incorrect output:
#include iostream
#include vector
#include string
std::ostream operator(std::ostream out, std::vectorstd::string const
items)
{
for(auto const item : items )
out item ;
return out;
}
int main()
{
std::cout \nGCC __VERSION__ std::endl;
std::vectorstd::string items {default};
auto add = [=](std::string item) mutable { items.push_back(item); return
items; } ;
std::cout add(one) std::endl;
std::cout add(two) std::endl;
std::cout add(three) std::endl;
}
$ g++-4.8 -std=c++11 -O2 -Wall -pedantic-errors main.cpp ./a.out
GCC 4.8.1
default one
two
three
which is incorrect output
[Bug c++/58924] New: Non-member invocation of overload of operator when the first argument is a temporary of type std::stringstream
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58924
Bug ID: 58924
Summary: Non-member invocation of overload of operator when
the first argument is a temporary of type
std::stringstream
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: sir_nawaz959 at yahoo dot com
I'm using GCC-4.8.1 in C++11 Mode.
Consider this code,
#include sstream
#include iostream
int main()
{
auto s = static_caststd::stringstream(std::stringstream() XYZ
ABC).str();
std::cout s std::endl;
}
Actual (incorrect) output:
XYZABC
The expected output is an address following by ABC, something like this:
0x400e83ABC
Because `std::stringstream()` is a temporary, so the first invocation of
`operator` must resolve to a member function (taking void* as argument) which
would print the address, and then the non-member function should be invoked for
the second ``.
Note that this works as expected when I don't use `-std=C++11` (of course, in
that case I use `std::string` instead of `auto`).
[Bug libstdc++/58924] Non-member invocation of overload of operator when the first argument is a temporary of type std::stringstream
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58924 --- Comment #5 from Sarfaraz Nawaz sir_nawaz959 at yahoo dot com --- (In reply to Fanael from comment #1) That's expected behavior AFAIU. 'operator(basic_ostreamcharT, traits os, const T x)' is a better match for const char[K] than 'basic_ostreamcharT,traits basic_ostreamcharT,traits::operator(const void* p)', hence the former gets called, which then forwards the arguments to 'operator(basic_ostreamcharT, traits os, const charT* x)'. Oh. I didn't come across this overload. Great that they've added this. Invalid bug.
[Bug libstdc++/56336] New: Buggy implementation of stoi, stol, stoll
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56336
Bug #: 56336
Summary: Buggy implementation of stoi, stol, stoll
Classification: Unclassified
Product: gcc
Version: 4.7.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: sir_nawaz...@yahoo.com
The following code-snippet should throw std::invalid_argument exception as per
the Standard, but they don't, instead they print `8978`:
//demo : http://stacked-crooked.com/view?id=4853f6694dc11f93ed9a687567e5166d
int main()
{
std::cout std::stoi(8978xyz) std::endl; //invalid argument
std::cout std::stol(8978xyz) std::endl; //invalid argument
std::cout std::stoll(8978xyz) std::endl; //invalid argument
}
The buggy part of the implementation is this:
//file : /4.7.2/include/c++/ext/string_conversions.h
//line : 60-61
//function : __stoa
if (__endptr == __str)
std::__throw_invalid_argument(__name);
Easy fix:
if (__endptr != (__str + std::strlen(__str)) )
std::__throw_invalid_argument(__name);
That should fix the bug. But it would be better to pass the length of the
string to the function. After all, `std::stoi` family takes the argument as
`std::string` which returns the size in O(1).
[Bug c++/52688] static local variable can accessed from local class of function template
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52688 --- Comment #6 from Sarfaraz Nawaz sir_nawaz959 at yahoo dot com 2012-03-26 15:54:46 UTC --- (In reply to comment #5) (In reply to comment #0) While gcc-4.5.1 compiles fine this code Are you sure? I get the same error with 4.1.2, 4.4.3, 4.5.2, 4.6.3 and 4.7.0 4.5.2 compiles and links OK with optimisation enabled, but so do the other versions I used ideone.com to compile it, which uses gcc-4.5.1 with -std=c++0x. http://ideone.com/Y2vIF I just noticed that though it compiles and links fine, but it doesn't print the expected output. :| Interestingly, when I remove `const` from the definition of the static local variable, and then I attempt to change it from the local class, it then gives error: http://ideone.com/vvwRc :-)
[Bug c++/52688] static local variable can accessed from local class of function template
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52688 --- Comment #3 from Sarfaraz Nawaz sir_nawaz959 at yahoo dot com 2012-03-24 15:25:22 UTC --- (In reply to comment #2) http://gcc.gnu.org/wiki/VerboseDiagnostics#missing_static_const_definition Jonathan, that is a different case. A static (const or otherwise) member of a class needs a definition in order to take its address, but the bug I reported is not about static member of a class, rather it is about a static variable local to a function template. Interestingly as I said, this code compiles fine in gcc-4.5.1, but not in gcc-4.6.1. Also, if I do the same in a non-template function, it works fine, as expected.
[Bug c++/52688] New: static local variable can accessed from local class of function template
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52688
Bug #: 52688
Summary: static local variable can accessed from local class of
function template
Classification: Unclassified
Product: gcc
Version: 4.6.1
Status: UNCONFIRMED
Severity: major
Priority: P3
Component: c++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: sir_nawaz...@yahoo.com
As per the C++ specification, static local variable can be accessed from local
class of function template, but GCC 4.6.1 gives error for the following
code-snippet:
templatetypename T
T f()
{
static const double staticLocalVariable = 100.0;
struct local
{
static double f() { return staticLocalVariable; }
};
return T(local::f());
}
int main() {
std::cout fdouble() std::endl;
}
While gcc-4.5.1 compiles fine this code, gcc-4.6.1 gives error, saying:
undefined reference to `staticLocalVariable'
