I just started using MinGW for Windows. When trying to create executable using
g++ a.cpp -o a.exe -std=c++14
for the code below:
#include <string>
using namespace std;
int main()
{
string x = to_string(123);
return 0;
}
I'm getting following error:
C:/mingw/bin/../lib/gcc/mingw32/5.3.0/../../../libmingwex.a(vsnprintf.o):(.text+0x0): multiple definition of vsnprintf
C:\Users\..\Local\Temp\cc4sJDvK.o:c:/mingw/include/stdio.h:426: first defined here
collect2.exe: error: ld returned 1 exit status
What is the root cause for this error and how can I make it go away? While I can easily find a replacement for to_string() function I'm not sure what is causing this error to occur in the first place.
Installing MinGW packages mingw32-libmingwex-* will link an appropriate version of vsnprintf and avoid the linker error.
This issue, i.e. multiple definition of vsnprintf, still exists in MinGW as December 2019.
After investigating a lot, I found the solution in the official mailing list.
It's a bug in mingwrt-5.2.2. Downgrading to the mingwrt-5.2.1 version solves that issue.
To do that, just input the following command:
mingw-get upgrade mingwrt=5.2.1
Then restart the MinGW shell.
Read the full story here.
Note: MinGW-w64 and MinGW are separate projects, so the accepted solution is not so helpful to me, as I want to keep MinGW and not to move to MinGW-w64.
I solved this issue using MinGW w64 compiler
download mingw-w64-install.exe
setup to Version: 6.3.0, Architecture: i686, Threads: posix, Exception: dwarf and Build revision: 2.
I hope this will be of some help.
There are multiple definitions of vsnprintf in both stdio.h and libmingwex.a. I am able to work this around by adding #define __USE_MINGW_ANSI_STDIO 0 to the start of the code, before any includes, which disables the definition of vsnprintf in stdio.h.
Related
UPDATE:
I've written a detailed tutorial that incorporates the top two answers on this question: http://blog.johannesmp.com/2015/09/01/installing-clang-on-windows-pt1/
TL;DR
On Windows, Given the following program:
#include <iostream>
int main()
{
int arr[] = {1, 2, 3, 4, 5};
for(auto el : arr)
{
std::cout << el << std::endl;
}
return 0;
}
I want to be able to do the following:
clang++ hello.cpp -o hello.exe -std=c++14
And get a 64 bit executable that just works. I don't want to have to append a ton of -I includes to tell clang where to find iostream or other standard c++ headers; I don't want to have to link in multiple steps.
I don't care so much about performance, efficiency, what linker is used, etc. I just want to be able to have clang/gcc/whatever set up correctly so that I can use a single, quick and dirty, console command like the one above.
What do I need to install for that to just work?
The Problem
As a predominately mac/linux user I'm used to being able to just use a package manager to install the latest version of clang, which just works.
I'm now trying to set up clang/gnu compiler on windows and it seems to be far more difficult, If only because there is little to no straightforward documentation out there (that I've been able to find)
I've tried to follow this tutorial: https://yongweiwu.wordpress.com/2014/12/24/installing-clang-3-5-for-windows - and was able to use it to get clang to build and link (using gcc 4.8.2), but the resulting binaries were 32 bit.
I've tried installing the latest prebuilt binaries of clang (3.6.2) and the 64 bit version of mingw-w64 (4.9.3 for 64 bit with posix and sjlj for exceptions), and am getting:
hello.cpp:1:10: fatal error: 'iostream' file not found
#include <iostream>
^
1 error generated.
Which seems to indicate that clang is not seeing gcc's files. It seems that some versions of LLVM/clang are looking for only certain versions of gcc, but that doesn't seem to be documented anywhere?
Similarly someone mentioned to me on the LLVM IRC that you need to modify clang's driver to look for gcc in certain paths?
What I'm looking for
I'm fine with building LLVM/Clang from source if necessary, but I'm really just looking for clear, step-by-step instructions that allow me to use clang++ as easily as I'm able to do with mac/linux
Something like:
Build this version of LLVM/Clang and place it in that directory
Download and install this version of cygwin (or mingw32 or mingw-w64) and install these packages.
etc..
Try installing MSYS2 and then installing the mingw-w64-x86_64-clang (binary) package:
pacman -S mingw-w64-x86_64-clang
It is a bit old at the moment (3.6.2), but it might be good enough for you. Then when you run the Win64 shell provided by MSYS2, clang will be on your path.
If it's not good enough, I have recently been building a 64-bit version of clang with MSYS2 and using it to compile native 64-bit Windows executables. My process was something like:
Use pacman to install base-devel, mingw-w64-x86_64-ninja, mingw-x86_64-cmake and perhaps some other packages that are needed by the build process.
Grab my PKGBUILD script for clang and the files in the same directory. This is based on the mingw-w64-clang-svn package from MSYS2, which is largely the work of Martell Malone. You can find him on the MSYS2 IRC channel and ask him more about it.
In a Win64, shell, go to the directory with my PKGDUILD, run export MINGW_INSTALLS=mingw64 (so you are only compiling the 64-bit version), and then run makepkg-mingw.
It is unlikely you will get everything right on the first try, and some files might need to be edited. Clang may have changed since the last time I did this and some patches might not apply cleanly.
if you use the upcoming clang 3.7.0, simply set PATH to include mingw-w64's bin, clang will work as you expect
You can install llvm pre-release binary for Windows here. MinGW-w64 can be downloaded here. Of course, you should make sure the paths are properly set up.
For the latest version of clang, e.g., clang 6.0.0. The above solution by #user5271266 will not be enough. Now the default target for clang Windows is x86_64-pc-windows-msvc (Assume that you are using 64 bit Windows).
In order to compile C++ source files, according to here, we should change the target:
clang++ -target x86_64-pc-windows-gnu -std=c++14 test.cc -o test.exe
I have:
-cygwin 1.7.25 on windows 7/32bit
-g++ --version --> g++ (GCC) 4.8.2
-libstdc++.a --> gcc-g++-4.8.2-1
Tried to make a c++
Hello World:
#include <string>
int main()
{
std::string s = "123";
int i = std::stoi(s);
}
compiling gives:
$ g++ -std=c++11 main.cpp
main.cpp: In function ‘int main()’:
main.cpp:6:10: error: ‘stoi’ is not a member of ‘std’
int i = std::stoi(s);
I searched for hours but I still could not find a solution. What's the issue here?
That's a bug, possibly an incomplete port of some library code to cygwin (it's a cplusplus11 feature) - some stuff has to be changed after all. Make sure to report it.
The solution is easy of course: #include <cstdlib> strtol(s.c_str(),0,10);
www.cplusplus.com/.../strtol
A similar mingw bug is mentioned also here
std::stoi doesn't exist in g++ 4.6.1 on MinGW
I have the same problem yesterday. "error: 'stoi' is not a member of 'std'."
First, I made sure c++11 was enabled. Then, I updated the g++ compiler to the newest version. After that, this error disappeared.
The compiler is not being taken seriously. On windows your best bet is to probably use visual studio, as it is always kept up to date . The bug here is that the macro defs are wrong to begin with. The problem starts from iomanip.h and iosbase . So they would have to changed all of there code. There are user made patches for this but I would not trust them at all, as they may contain even more bugs then the original copies. But it's up to you , I just stick with visual studio express edition.
stoi works correct only on mingw64 for me.
If you use Codeblocks, don't forget to check if your projects compiler is set to mingw64.
Well, I am working with -std=c++98, not -std=c++11 but I solved it with the following:
int i = std::atoi(input.c_str());
atoi() is waiting for c type null-terminated string, c_str() makes it null-terminated char*. To use atoi I also() added the following library:
#include <cstdlib>
my system is:
Ubuntu 22.04.1 LTS
I've just compiled GCC 4.7 to work with stdatomic.h, but I can't seem to -I it. stdatomic.h seems to live in /usr/include/c++/4.4.3, but then the linker tells me it needs a bunch of other files in dirs nearby. If I -I all of them, I still get the error undefined reference to atomic_flag_clear_explicit. Any ideas how I'm supposed to link this right?
First, if you are compiling with GCC 4.7 you should not be including or linking anything from a directory from GCC 4.4.
Second, -I only affects the search path for header files. "undefined reference" is a linker error and usually means it hasn't found the right library. You change the library search path with -L. The linker didn't say it didn't find a library with the right name, it says it didn't find a symbol, so clearly the library it did find didn't have that symbol. I'd suggest you have a versioning problem, perhaps caused by a installation problem.
The <stdatomic.h> header in GCC 4.4 and 4.5 was from an early draft of C++0x atomics, but is not part of the final standard, so it was removed from libstdc++.
The C++ compiler supports C++11 atomics via the C++11 <atomic> header, so you should use that header in C++ code.
When the C compiler supports C11 atomics, the <stdatomic.h> header will be provided again.
Using this command solved the problem for me:
$ scl enable devtoolset-7 bash
I got the same error as you when entering sudo make altinstall for installing Python 3.8.5 on CentOS 7.
On an almost default install of Ubuntu 11.04 I installed clang.
I am trying to compile this:
#include <cstdlib>
int main(){
return 0;
}
g++ can deal with it just fine, but clang++ errors out: fatal error: 'cstdlib' file not found
Can someone explain why this happens? and what needs to be done to make this work?
I expected clang++ to be a drop-on replacement for g++.
Seems like your clang build is not searching the correct platform include paths. Try checking with
clang -v ...
where it is looking for headers (and check that your platform include paths are there). You might have to add additional include directories (e.g. /usr/include/c++/x.y).
You might want to take a look at the source file lib/Frontend/InitHeaderSearch.cpp, The method AddDefaultCPlusPlusIncludePaths does some distribution/gcc-version specific magic (I had to fix it for my own system once).
I have build a g++ v4.4 from source by using the archives provided by gcc.gnu.org.
But the resulting g++ cannot compile some of our projects c++ files. I am receiving a message simply saying: assembler error. It turned out that the assembler chokes on some extremely long symbol names, e.g. symbols names with a length of more then 2k.
Am I missing something to get it to work?
I would very appreciate an advice on how to get this working!
Environment: Debian-Lenny 64bit
EDIT: The mentioned c++ files are compiling fine with g++ versions v4.2 and v4.3. So I don't think it is a bug in the assembler (from binutils v2.18). Just to be sure I have also tried with binutils v2.20 - but I got the identical error message.
EDIT: I need g++ v4.4.x for the purpose of comparing the output of different g++ versions (and there is no g++ v4.4 in the official lenny repositories)
If your analysis is correct, it seems the proper course of action would be to file a bug for binutils. Or gcc, if it turns out the long symbol names are due to a bug in gcc's name mangling.
Of course, a (preferably reduced) testcase will help the developers fix your problem. Heck, it could have helped SO readers to verify your problems.
You're going to have to compile the corresponding gas instead of depending on what lenny has in his refrigerator (/usr/bin).
Why don't a) upgrade or b) use the backports archive or c) rebuild from current Debian sources on your box? I happily run testing with g++ 4.2, 4.3 and 4.4.
Worst case, you could install a new Debian release in a virtual environment such as a chroot, a Xen or Kvm instance, or inside VirtualBox.