File not found: using array class in C++ - c++

Here is the code: error shows up for line 8 of main.hpp .
//main.hpp
#ifndef MAIN_HPP // if main.hpp hasn't been included yet...
#define MAIN_HPP // #define this so the compiler knows it has been included
#include <array> // OFFENDING LINE 8
using std:array
class Quicksort {
public:
void sort(array);
};
#endif
This header is being used by this c++ file.
#include "main.hpp"
// this is just the start of a quicksort algorithm, base case only
void Quicksort::sort (array list) {
if (list.size == 1 || list.size == 0) {
return;
}
}
Why am I getting this error? I thought my C++ and g++ were fine. Any other reasons it might not be working?
I'm compiling with the command (on Mac, with newest X-Code): g++ version 4.2
g++ -Wall -c quicksort.cpp
When I use -std=c++11 it says:
unrecognized command line option "-std=c++11"

You need C++11 support to be able to include <array>. On GCC you would need to use the -std=c++0x flag (or -std=c++11 on the latest versions).
Furthermore, array lives in the std namespace, and you probably mean to pass a reference:
void sort(std::array&);
If your compiler does not support the relevant parts of C++11, you can use the version from TR1:
#include <tr1/array>
...
std::tr1::array<int, 5> a = ...;

You forgot to include -std=c++11 or -std=gnu++11 (-std=c++0x and -std=gnu++0x on older versions of GCC before 4.7.0), the latter which includes extensions. If that still doesn't work then you need a more recent version of GCC.

Related

Intel-Compiler fails C++14-check with `attribute "__malloc__" does not take arguments`

I have the following code (intended to detect if the compiler supports C++14):
#include <memory>
#include <algorithm>
// Check the version language macro, but skip MSVC because
// MSVC reports 199711 even in MSVC 2017.
#if __cplusplus < 201402L && !defined(_MSC_VER) && !defined(__INTEL_COMPILER)
#error "insufficient support for C++14"
#endif
int main()
{
auto ptr = std::make_unique<int>(42);
constexpr int max = std::max(0, 1);
(void) ptr;
(void) max;
return 0;
}
When compiling it with g++ (version 11.2.1) and the line g++ -std=c++14 test.cpp -o test it works fine. When compiling it with the intel compiler (version 2021.3.0 (gcc version 11.2.1 compatibility)) instead using icpc -std=c++14 test.cpp -o test, it fails with
In file included from /usr/include/c++/11/cwchar(44),
from /usr/include/c++/11/bits/postypes.h(40),
from /usr/include/c++/11/iosfwd(40),
from /usr/include/c++/11/bits/shared_ptr.h(52),
from /usr/include/c++/11/memory(77),
from test.cpp(1):
/usr/include/wchar.h(155): error: attribute "__malloc__" does not take arguments
__attribute_malloc__ __attr_dealloc_free;
^
In file included from /usr/include/c++/11/cstdlib(75),
from /usr/include/c++/11/bits/stl_algo.h(59),
from /usr/include/c++/11/algorithm(62),
from test.cpp(2):
/usr/include/stdlib.h(565): error: attribute "__malloc__" does not take arguments
__attr_dealloc_free;
^
In file included from /usr/include/c++/11/cstdlib(75),
from /usr/include/c++/11/bits/stl_algo.h(59),
from /usr/include/c++/11/algorithm(62),
from test.cpp(2):
/usr/include/stdlib.h(569): error: attribute "__malloc__" does not take arguments
__THROW __attr_dealloc (reallocarray, 1);
^
In file included from /usr/include/c++/11/cstdlib(75),
from /usr/include/c++/11/bits/stl_algo.h(59),
from /usr/include/c++/11/algorithm(62),
from test.cpp(2):
/usr/include/stdlib.h(797): error: attribute "__malloc__" does not take arguments
__attr_dealloc_free __wur;
^
compilation aborted for test.cpp (code 2)
What exactly is going wrong here, and how can I fix it?
Short update: Looks as if CUDA is running into similar issues, and it might be related to glibc 2.34: https://forums.developer.nvidia.com/t/cuda-11-5-samples-throw-multiple-error-attribute-malloc-does-not-take-arguments/192750/15
Compiling and executing the shared code using icpc 2021.4 and it runs fine.
Used below command to compile the code.
icpc -std=c++14
Below are the environment details.
Operating System: Ubuntu 18.04.3 LTS
Kernel: Linux 4.15.0-76-generic
For compatibility, Kindly refer the link for Intel® C++ Compiler Classic System Requirements
https://software.intel.com/content/www/us/en/develop/articles/oneapi-c-compiler-system-requirements.html

error : to_string was not declared in this scope

I am compiling the code on solaris 5.11.
G++ version is 4.8.2.
The same code works on Ubuntu but gives the error: 'to_string() was not declared in this scope' on solaris.
I went through many links and tried the following things:
Adding 'std::' before to_string(). This gives error - 'to_string is not a member of std'
Added 'std=c++11' or 'std=c++0x' while compilation.
Both the above things do not work.
Is there anything related to Solaris?
The actual code was very huge. So simulating the error in sample code below.
temp.cpp
#include<iostream>
#include<string>
using namespace std;
int main()
{
string str;
int i = 10;
str = "john age is " + to_string(i);
cout << str;
return 0;
}
command: g++ temp.cpp -std=c++0x -o temp
For GCC 4.8.2 the to_string functions are defined conditionally, according to the following:
#if ((__cplusplus >= 201103L) && defined(_GLIBCXX_USE_C99) \
&& !defined(_GLIBCXX_HAVE_BROKEN_VSWPRINTF))
The GLIBCXX_USE_C99 macro depends on a large number of C99 functions being supported by the OS, so presumably the necessary C99 library functions were not found when building GCC on Solaris. So the to_string definitions are absent.
In current versions of GCC the condition is more fine-grained, and checks whether the C99 functions are defined in C++98 mode and C++11, so that the absence of any C99 function doesn't disable everything:
#if __cplusplus >= 201103L
//...
#if _GLIBCXX_USE_C99_STDIO
It's not possible to backport these improvements to GCC 4.8, so you might need to update to at least GCC 6.
compile using std=c++11 as below
g++ -std=c++11 filename.cc
Note : your compiler must support c++11

Compiling error: to_string is not a member of std [duplicate]

Okay, so I have
tmp.cpp:
#include <string>
int main()
{
std::to_string(0);
return 0;
}
But when I try to compile I get:
$ g++ tmp.cpp -o tmp
tmp.cpp: In function ‘int main()’:
tmp.cpp:5:5: error: ‘to_string’ is not a member of ‘std’
std::to_string(0);
^
I'm running g++ version 4.8.1. Unlike all the other references to this error that I found out there, I am not using MinGW, I'm on Linux (3.11.2).
Any ideas why this is happening? Is this standard behaviour and I did something wrong or is there a bug somewhere?
you may want to specify the C++ version with
g++ -std=c++11 tmp.cpp -o tmp
I don't have gcc 4.8.1 at hand , but in older versions of GCC,
you can use
g++ -std=c++0x tmp.cpp -o tmp
At least gcc 4.9.2 I believe also support part of C++14 by specifying
g++ -std=c++1y tmp.cpp -o tmp
Update:
gcc 5.3.0 (I am using the cygwin version) supports both -std=c++14 and -std=c++17 now.
to_string works with the latest C++ versions like version 11. For older versions you can try using this function
#include <string>
#include <sstream>
template <typename T>
std::string ToString(T val)
{
std::stringstream stream;
stream << val;
return stream.str();
}
By adding a template you can use any data type too.
You have to include #include<sstream> here.

"to_string" isn't a member of "std"?

Okay, so I have
tmp.cpp:
#include <string>
int main()
{
std::to_string(0);
return 0;
}
But when I try to compile I get:
$ g++ tmp.cpp -o tmp
tmp.cpp: In function ‘int main()’:
tmp.cpp:5:5: error: ‘to_string’ is not a member of ‘std’
std::to_string(0);
^
I'm running g++ version 4.8.1. Unlike all the other references to this error that I found out there, I am not using MinGW, I'm on Linux (3.11.2).
Any ideas why this is happening? Is this standard behaviour and I did something wrong or is there a bug somewhere?
you may want to specify the C++ version with
g++ -std=c++11 tmp.cpp -o tmp
I don't have gcc 4.8.1 at hand , but in older versions of GCC,
you can use
g++ -std=c++0x tmp.cpp -o tmp
At least gcc 4.9.2 I believe also support part of C++14 by specifying
g++ -std=c++1y tmp.cpp -o tmp
Update:
gcc 5.3.0 (I am using the cygwin version) supports both -std=c++14 and -std=c++17 now.
to_string works with the latest C++ versions like version 11. For older versions you can try using this function
#include <string>
#include <sstream>
template <typename T>
std::string ToString(T val)
{
std::stringstream stream;
stream << val;
return stream.str();
}
By adding a template you can use any data type too.
You have to include #include<sstream> here.

std::thread error (thread not member of std)

I compiled & installed gcc4.4 using macports.
When I try to compile using -> g++ -g -Wall -ansi -pthread -std=c++0x main.cpp...:
#include <thread>
...
std::thread t(handle);
t.join();
....
The compiler returns:
cserver.cpp: In member function 'int CServer::run()':
cserver.cpp:48: error: 'thread' is not a member of 'std'
cserver.cpp:48: error: expected ';' before 't'
cserver.cpp:49: error: 't' was not declared in this scope
But std::cout <<... compiles fine..
Can anyone help me?
gcc does not fully support std::thread yet:
http://gcc.gnu.org/projects/cxx0x.html
http://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html
Use boost::thread in the meantime.
Edit
Although the following compiled and ran fine for me with gcc 4.4.3:
#include <thread>
#include <iostream>
struct F
{
void operator() () const
{
std::cout<<"Printing from another thread"<<std::endl;
}
};
int main()
{
F f;
std::thread t(f);
t.join();
return 0;
}
Compiled with
g++ -Wall -g -std=c++0x -pthread main.cpp
Output of a.out:
Printing from another thread
Can you provide the full code? Maybe there's some obscure issue lurking in those ...s?
I had the same issue on windows using MinGW. I found wrapper classes for in on github mingw-std-threads Including
mingw.mutex.h, mingw.thread.h files to global MinGW directory fixed this issue. All I had to do is to include header file and my code stayed the same
#include "mingw.thread.h"
...
std::thread t(handle);
...
Drop -ansi, it means -std=c++98, which you obviously don't want. It also causes macro __STRICT_ANSI__ to be defined and this may change the behavior of the headers, e.g. by disabling C++0x support.