I try to crosscompile some c++11 source with mingw on linux for windows. The code uses std::thread.
When i compile i always get some errors:
$ ../mingw/cross/bin/i686-w64-mingw32-g++ -std=c++11 -I include/ test.cpp -lstdthread -otest
In file included from test.cpp:4:0:
...
error: 'thread' in namespace 'std' does not name a type
...
I it possible to enable c++11 threads in mingw? The code compiles without any problems with the local g++.
Thank you,
regars
Kevin
-edit-
I just downloaded the mingw somewhere in the internet, because i tried to get an as new as possible version:
../mingw/cross/bin/i686-w64-mingw32-g++ -v
Using built-in specs.
COLLECT_GCC=../mingw/cross/bin/i686-w64-mingw32-g++
COLLECT_LTO_WRAPPER=/home/bmeier/source/mingw/cross/bin/../libexec/gcc/i686-w64-mingw32/4.8.1/lto-wrapper
Target: i686-w64-mingw32
Configured with: /home/drangon/work/mingw-w64-dgn_32/source/gcc-4.8.1/configure --target=i686-w64-mingw32 --disable-nls --disable-multilib --with-gmp=/home/drangon/work/mingw-w64-dgn_32/build/for_cross --with-mpfr=/home/drangon/work/mingw-w64-dgn_32/build/for_cross --with-mpc=/home/drangon/work/mingw-w64-dgn_32/build/for_cross --with-isl=/home/drangon/work/mingw-w64-dgn_32/build/for_cross --with-cloog=/home/drangon/work/mingw-w64-dgn_32/build/for_cross --enable-languages=c,c++,objc,obj-c++ --disable-libstdcxx-pch --prefix=/home/drangon/work/mingw-w64-dgn_32/cross --with-sysroot=/home/drangon/work/mingw-w64-dgn_32/cross
Thread model: win32
gcc version 4.8.1 (GCC)
regards
Kevin
There is already a native implementation of std::thread and sync primitives, that works with any C++11 version of MinGW:
https://github.com/meganz/mingw-std-threads
Basically MinGW does not support threads on windows see the following link: http://www.cplusplus.com/forum/windows/82461/
Specifically _GLIBCXX_HAS_GTHREADS is not defined and the class thread in the header thread requires it. (It is built on gthreads).
You should try and use boost::thread for a win/linux compatible thread class
Most probably you might have forgot to include thread header #include <thread>
Related
What I have:
I am writing Qt application for Linux (I work in Linx Mint 17.3 64-bit)
I use C++11 features in my Qt project (Qt ver 5.5)
I want to add libslave to my Qt project.
libslave uses deprecated (for C++11) boost::function, boost::shared_ptr, boost::bind and boost::any.
My trouble:
When I compile with gcc (v the whole project or only library with -std=c++11 flag boost crashes with many errors. Qt Creator shows about 4000 errors, but they are pretty similar and look like:
typedef boost::function< void( RecordSet& )> callback;
is not complete type
BOOST_NOEXCEPT'does not name a type
~any() BOOST_NOEXCEPT
etc...
I have tried to rewrite library with C++11 std library, but std does not containg boost::any analog, so that was bad idea.
Question:
How to compile boost (or at least libslave) with c++11?
Boost Version: 1.54 (from repo)
g++ version: 4.8.4 (from repo)
Qt version: 5.5 (downloaded from Official Site)
Linux Mint: 17.3 Rosa
UPDATE:
Example:
You can download code what I try to compile by this link.
Instruction:
Download tarball
Extract
Go to folder and just type make (all works fine)
Open MakeFile and replace CXX variable to
CXX = g++ -std=c++11
Try to make again and you'll get errors.
P.S.
To compile library you'll need libmysqld-dev, libboost-all-dev, libmysqlclient-dev.
Probably you'll need something else, but I don't remeber. Sorry.
I found the hack and it works for me.
I replace boost::bind usage in file nanomysql.h to std::bind by such strings:
...
typedef std::map<std::string, field> value_t;
typedef std::vector< value_t > result_t;
void store(result_t& out)
{
//You need specify template because of push_back has overloads
auto hack = std::bind<void(result_t::*)(const value_t&)>(&result_t::push_back, &out, _1);
use(hack);
}
...
And replace all boost::shared_ptr, boost::function to std::shared_ptr and std::function in all files in library.
After this everything compiles and work fine with -std=c++11 flag.
Whole code of nanomysql.h you can see here:
Link to code
Use actual fork of libslave - https://github.com/vozbu/libslave with support c++11. Support for mysql 5.6 and 5.7 will be soon
Why does specifying -std=c++11 when compiling a program that directly or indirectly uses std::thread not imply -pthread? It seems strange that the implementation detail of std::thread using pthreads under the hood is exposed to the programmer; if it's a matter of giving the user a choice of posix-compatible threading libraries, why not just default to pthreads and have some --threading-model=<your_favorite_posix_threads_library> argument to override it?
The -pthread option is not universally required to use std::thread - it's an implementation quirk of whatever platform you're building on.
Compiling:
#include <thread>
#include <iostream>
int main()
{
std::thread t{[]()
{
std::cout << "Hello World\n";
}};
t.join();
return 0;
}
with
clang -std=c++11 ThreadTest.cpp -lc++
On MacOSX, builds and runs, and if we do:
otool -L a.out
a.out:
/usr/lib/libc++.1.dylib (compatibility version 1.0.0, current version 120.1.0)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1225.0.0)
We can see that we've needed to link nothing extra to make this work - nor has it happened behind the scenes. It seems to be very much a platform implementation detail that pthreads is a separate library.
Having a choice of threading libraries with the pthread interface is legacy baggage on *NIX systems, many of which started off without thread support, then went through a phase of user-space threads before having full kernel support. I guess it's still there because nobody likes making breaking changes.
I need to compile C/C++ pthread and socket code in windows 8 where I've installed MicGW GCC and G++ 4.7.
When I compile my test code using g++ test.cpp -o test
Code is:
#include<iostream>
#include<sys/socket.h>
#include<sys/types.h>
using namespace std;
int main() {
cout<<"Got Socket";
}
This gives error fatal error: sys/socket.h not found and the
same occur with types.h
The error I found is that cygwin is using MicGW GCC and g++ but I want it to use its own instead of MinGW's so that I can include Linux libraries.
I have not been able to reproduce your problem on my Cygwin.
Are the headers present in /usr/include/sys?
Search the sys folder in [installed directory]/usr/include if the socket.h was not there download one Copy it there manually.
don't afraid of manual works ;-)
The Scenario
I am developing an application in C99 ANSI C that uses OpenMP and GMP. It's natural habitat will be a linux machine with plenty of cores, so there's basically no big trouble there, but for reasons I do not want to debate here, I have to develop under Cygwin on a 64 bit Windows machine.
When I use the 32 bit version of gcc, something, somewhere, goes horribly wrong and the application is about 60 times slower than a very crude single-threaded version, when it should in fact be faster by a factor that equals the number of CPU's. It makes it impossible to work with. I really don't know what is causing this; Anyway, I have decided to use the 64 bit version of MinGW instead, that'd be x86_64-w64-mingw32-gcc-4.5.3 and his friends, to be precise.
A side note: I am sure that the slowdown is not a flaw in my multithreading, the multithreaded application works correctly and faster on the linux machine.
The actual Problem
Setting up GMP was easy, it can be compiled from source without any trouble and then works like a charm. Compiling the following easy example with -fopenmp also works like a charm:
#include <gmp.h>
#include <omp.h>
int main() {
#pragma omp parallel
{
mpz_t t;
mpz_init(t);
mpz_set_si(t,omp_get_thread_num());
# pragma omp critical
{
gmp_printf("Hello From GMP'd Thread %Zd!\n",t);
fflush(stdout);
}
mpz_clear(t);
}
return 0;
}
However, executing it gives me
$ ./test
test.exe: error while loading shared libraries: ?:
cannot open shared object file: No such file or directory
I am aware of this question, but I would like to make this work without downloading any binaries other than those from an official Cygwin repository. Since my example compiled with the -fopenmp switch, I am convinced that this should also be very much possible.
Can someone help me with that? Thanks a bunch in advance.
I think that "error while loading shared libraries: ?:" means that cygwin does not know where to find libgmp-10.dll and/or libgomp-1.dll.
Both DLL are required according to Dependency Walker
Your program worked after I added the directory that contains both DLL to my PATH:
#$ x86_64-w64-mingw32-g++ -fopenmp -o w64test gmp_hello.c -lgmp
#$ file ./w64test.exe
./w64test.exe: PE32+ executable (console) x86-64, for MS Windows
#$ ./w64test.exe
/home/david/SO/hello_openmp/w64test.exe: error while loading shared
libraries: ?: cannot open shared object file: No such file or
directory
#$ ls /cygdrive/c/dev/cygwin/usr/x86_64-w64-mingw32/sys-root/mingw/bin/*mp*dll
/cygdrive/c/dev/cygwin/usr/x86_64-w64-mingw32/sys-root/mingw/bin/libgmp-10.dll
/cygdrive/c/dev/cygwin/usr/x86_64-w64-mingw32/sys-root/mingw/bin/libgomp-1.dll
#$ export PATH=$PATH:/cygdrive/c/dev/cygwin/usr/x86_64-w64-mingw32/sys-root/mingw/bin/
#$ ./w64test.exe
Hello From GMP'd Thread 1!
Hello From GMP'd Thread 0!
note
I compiled and installed gmp-5.0.5 with the following commands:
./configure --build=i686-pc-cygwin --host=x86_64-w64-mingw32 --prefix=/usr/x86_64-w64-mingw32/sys-root/mingw --enable-shared --disable-static
make -j 2
make check
make install
update
Your program also works with cygwin "GCC Release series 4 compiler".
#$ g++ -fopenmp -o cygtest gmp_hello.c -lgmp
#$ ./cygtest.exe
Hello From GMP'd Thread 1!
Hello From GMP'd Thread 0!
#$ g++ -v
Target: i686-pc-cygwin
Thread model: posix
gcc version 4.5.3 (GCC)
You might need to install the following packages:
libgmp-devel (Development library for GMP)
libgmp3 (Runtime library for GMP)
libgomp1 (GOMP shared runtime)
Normally I can google my way around and find solutions, but not this time.
I'm using 64 bit Linux Ubuntu 11.04 to compile a 32 bit windows application. I'm using i586-mingw32msvc-gcc to compile my C++ files.
test.cpp:
#include <boost/asio.hpp>
makefile:
i586-mingw32msvc-gcc -c -m32 -mthreads -o test.o test.cpp
Error:
boost/asio/detail/socket_types.hpp:
# include <sys/ioctl.h>
doesn't exist.
Added to makefile: -DBOOST_WINDOWS
Error:
# warning Please define _WIN32_WINNT or _WIN32_WINDOWS appropriately
Ok, added to makefile: -D_WIN32_WINNT=0x0501
Error:
# error "Compiler threading support is not turned on. Please set the correct command line options for threading: -pthread (Linux), -pthreads (Solaris) or -mthreads (Mingw32)"
Yet I did specify -mthreads.
Adding -DBOOST_HAS_THREADS might be sufficient (see # elif defined __GNUC__ from the offending header). But it's likely/possible that your boost installation has been crafted to support your build environment and not your target. Try building it yourself with your cross-compiling toolchain.
It turned out that I had a set of #undef and #defines to force the GLIBC version to something that allowed me to compile for Linux (not cross compile) RHEL5, which otherwise would give me all kinds of other errors. Turns out that when cross compiling for windows using mingw, that force feeding the GLIBC version causes boost to take a strange path leaving various aspects undefined, including the bahavior or availability of threading. I surrounded it with an #ifndef _WIN32 which made the problem go away.
Maybe that -mthreads argument needs to come last.