I am working on a programming assignment, and it requires me to read a json file. To do so I am using https://github.com/nlohmann/json. When I #include "json.hpp" I get errors. I am guessing this is occurring because I need to encode it correctly for Mac. But I am not sure how to do so! Would anyone be able to help me with the same?
Here is an image of my compiler ouput
That library is written in C++11 (as per the documentation).
Your compiler is not using C++11 by default. To fix it will require something like this:
g++ -std=c++11 ...
If it complains that -std=c++11 is not valid, try -std=c++0x (an obsolete synonym).
Related
Sort briefing what I am trying to do:
I want to use vnode-lp on my windows PC. I’ve installed MinGW. I’ve installed the necessary dependencies like LAPACK & BLAS libraries as well as Profil/BIAS. The installation of all libraries passed the make and make install process without errors. I hope (!) I’ve managed to install it correctly.
Now the Problem:
Now I’ve tried to get a simple program compiled with basically northing in it just an #include “vnode.h”. First I tried it with Microsoft Visual Studio. Since this gave me several errors I tried to compile it with g++ using MinGW. This gives me the same errors. It starts with
./matrix.w:90:17: error: ‘v_bias’ is not a namespace-name
The Question:
How to include vnodelp into an c++ program and compile it without errors under windows, am I missing something?
Off-topic:
I am trying to get this running for over a week now and don’t know what to do anymore.
C++ is most definitely not C, and packages designed for C++ will never compile and run as C code. So, what you're trying to do really can't be done unless you do some fancy stuff by creating a .dll or something like that, and even then I think you wouldn't get the functionality you want. Why not write your code in C++ and compile with g++ or a similar compiler?
I have managed to finally solve this issue. In case someone has the same problem here is the solution.
I have missed something in the call. Here is the full call that has worked for me:
g++ -o2 –Wall –Wno-deprecated –DNDEBUG – DPROFIL_VNODE – DMAXORDER=50 –I(path to profil bias)/include –I(path to profil bias)/include/BIAS –I(path to profil bias)/src/Base –I(path to vnodelp)/FADBAD++ -I../include –DNDEBUG –c –o (filename).o (filename).cc
g++ -L(path to profil bias)/lib –L(path to lapack)/lib –L../lib –o (filename) (filename).o –lvnode –lProfil –lBias –llr (path to lapack)/lib/liblapack.lib (path to lapack)/lib/libblas.lib –lstd++
funfact:
This also complies with gcc instead of g++
I am running Cygwin on windows 8, attempting to compile the source code for a game I would like to mod. Unfortunately I am running into some errors while building involving the fileno function. After doing some googling It seems like the problem might have to do with c++11 support (I'm not really sure what this means). Most of the solutions people have found involve adding some option like -std=c++0x or -std=c++11 when compiling, but my attempts to add the options into the makefile have been unsuccessful, and I don't know if that's whats causing the problem anyways. I'll include the code snippet that's throwing the error and a link to the makefile as it is quite large. Any advice you could give me would be great.
code that throws error:
time_t file_modtime(FILE *f)
{
struct stat filestat;
if (fstat(fileno(f), &filestat))
return 0;
return filestat.st_mtime;
}
Link to Makefile
it is being hosted on github
EDIT: After getting some advice I poked around the makefile and found five instances where the -std option was used, playing around with them hasn't changed anything. Is the problem with my Cygwin configuration? I installed the packages I was told I would need in the installation guide for the game I am building.
Changing the -std=c*** in your makefile to -std=gnu++0x should fix your problem.
If you don't know what c++11 is you're most likely not using it anyway.
Also if you need c++11 support you can also do: -std=gnu++11 instead of -std=gnu++0x
For windows...
fileno() is deprecated: https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/posix-fileno?view=vs-2017
use _fileno() instead: https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/fileno?view=vs-2017
I was wondering if someone could help me with this.
I've retrieved the source code for the gnuplot-iostream interface from http://www.stahlke.org/dan/gnuplot-iostream/. However, when I attempt to compile the code using the command:
]$ cmake .; make
I get the following compiler error
/.../gnuplot-iostream.h: In constructor ‘Gnuplot::Gnuplot(const std::string&)’:
/.../gnuplot-iostream.h:427: error: ‘never_close_handle’ is not a member of ‘boost::iostreams’
I'm using Scientific Linux 6.2 (kernal 2.6.32-220.23.1.el6.x86_64), g++ 4.4.6, and have boost libraries installed (/usr/include/boost/iostreams/ exists).
Any assistance would be very much appreciated.
D
enum file_descriptor_flags was added in boost::iostreams only in 1.44.0.
enum file_descriptor_flags
{
never_close_handle = 0,
close_handle = 3
};
So, the solution is simply update the boost library (thanks ForEveR).
If however, like me, you do not have the access to update the libraries on your system you should note that I was able to force compilation and obtain basic functionality by simply replacing the two occurrences of boost::iostreams::never_close_handle in the gnuplot-iostream.h file with 0.
I am currently writing a CUDA application and want to use the boost::program_options library to get the required parameters and user input.
The trouble I am having is that NVCC cannot handle compiling the boost file any.hpp giving errors such as
1>C:\boost_1_47_0\boost/any.hpp(68): error C3857: 'boost::any': multiple template parameter lists are not allowed
I searched online and found it is because NVCC cannot handle the certain constructs used in the boost code but that NVCC should delegate compilation of host code to the C++ compiler. In my case I am using Visual Studio 2010 so host code should be passed to cl.
Since NVCC seemed to be getting confused I even wrote a simple wrapper around the boost stuff and stuck it in a separate .cpp (instead of .cu) file but I am still getting build errors. Weirdly the error is thrown upon compiling my main.cu instead of the wrapper.cpp but still is caused by boost even though main.cu doesn't include any boost code.
Does anybody know of a solution or even workaround for this problem?
Dan, I have written a CUDA code using boost::program_options in the past, and looked back to it to see how I dealt with your problem. There are certainly some quirks in the nvcc compile chain. I believe you can generally deal with this if you've decomposed your classes appropriately, and realize that often NVCC can't handle C++ code/headers, but your C++ compiler can handle the CUDA-related headers just fine.
I essentially have main.cpp which includes my program_options header, and the parsing stuff dictating what to do with the options. The program_options header then includes the CUDA-related headers/class prototypes. The important part (as I think you've seen) is to just not have the CUDA code and accompanying headers include that options header. Pass your objects to an options function and have that fill in relevant info. Something like an ugly version of a Strategy Pattern. Concatenated:
main.cpp:
#include "myprogramoptionsparser.hpp"
(...)
CudaObject* MyCudaObj = new CudaObject;
GetCommandLineOptions(argc,argv,MyCudaObj);
myprogramoptionsparser.hpp:
#include <boost/program_options.hpp>
#include "CudaObject.hpp"
void GetCommandLineOptions(int argc,char **argv,CudaObject* obj){
(do stuff to cuda object) }
CudaObject.hpp:
(do not include myprogramoptionsparser.hpp)
CudaObject.cu:
#include "CudaObject.hpp"
It can be a bit annoying, but the nvcc compiler seems to be getting better at handling more C++ code. This has worked fine for me in VC2008/2010, and linux/g++.
You have to split the code in two parts:
the kernel have to be compiled by nvcc
the program that invokes the kernel has to be compiled by g++.
Then link the two objects together and everything should be working.
nvcc is required only to compile the CUDA kernel code.
Thanks to #ronag's comment I realised I was still (indirectly) including boost/program_options.hpp indirectly in my header since I had some member variables in my wrapper class definition which needed it.
To get around this I moved these variables outside the class and thus could move them outside the class defintion and into the .cpp file. They are no longer member variables and now global inside wrapper.cpp
This seems to work but it is ugly and I have the feeling nvcc should handle this gracefully; if anybody else has a proper solution please still post it :)
Another option is to wrap cpp only code in
#ifndef __CUDACC__
I have the following very simple application that compiles and runs fine:
EDIT: changed the example to be simpilar to end confusion of the real issue
int main() {
return 0;
}
As soon as I add #include <string> (and not even reference std::string), it fails to compile and I get the following error:
/usr/include/c++/4.1.2/bits/allocator.h:82 error: expected template-name before '<' token
Along with about 456 other, similar errors.
Any ideas? Thanks!
UPDATE:
Line 82 of /usr/include/c++/4.1.2/bits/allocator.h references the template __glibcxx_base_allocator at the location of the error. That template is defined in bits/c++allocator.h. When I search the system for that file, I get 3 hits, but none of them are in /usr/include/c++/4.1.2/bits/ as one would expect.
I have version 3.1.6, 4.1.1, and 4.3.2, but not 4.1.2 as the rest of the includes I am using. I am not sure which one is being used (if any, however, I don't get any error for an unknown file), but it seems the problem may stem from this.
The problem appears to be the installed development packages are not correct or incomplete (not to be confused with corrupt). Forcing g++ to use different include versions corrects that:
g++ -nostdic++ hello.cc -o hello -I/usr/include/c++/3.4.6
All the alternative directories (4.1.1, 4.1.2 and 4.3.2) are incomplete causing inappropriate files to be included causing the unusually errors. For example:
/usr/include/c++/4.1.2/bits/allocator.h requires __glibcxx_base_allocator located in bits/c++allocator.h which is being included from either /usr/include/c++/4.1.1 or /usr/include/c++/4.3.2 and appear to be incompatible. Forcing the compiler to use the only complete set of includes rectifies this.
Almost certainly g++ is detecting .cc as a C source file, not C++ and passes it through to gcc instead of compiling as C++. You can easily test by renaming your file to hello.C. There's also a language parameter to g++ you can use.
EDIT: This seems to work fine in g++ 4.2 with a .cc extension so that might not be it. Do you have any other headers included you aren't showing us? They could be interfering with <string>.
EDIT2: Alternatively your headers might not be set up right. Does this work:
#include <string>
int main()
{
return 0;
}
Errors like this have been heard of to occur when the C++ standard library headers are corrupted/not fully installed – maybe there is even a message referring to a missing include among your 456 other errors.
In any case, make sure that libstdc++-devel, resp. the package containing the C++ standard library header files of your distribution, is properly installed.
Check your include path. The paths can be specified as environment variables or specified on the command line. You could be using an include file from a different compiler or different version of the same compiler.
Also, try using <cstdio> rather than <stdio.h>.
Another suggestion: change <> to "".
This could be error caused at preprocess stage. Just preprocess your cpp file by passing flag -E to gcc and Look at the place the compiler complains.