I just installed YCM on CentOS 7. I am now at the step of generating a ".ycm_extra_conf.py" equivalent of the file for my project, which is a nested directory of c++ files, uses Scons build system and g++ (with -std=c++98) to compile the c++ files.
I have few questions:
Are the contents of the "flags" variable in ".ycm_extra_conf.py"
file the flags that are passed to the project compiler, in my case
the g++ compiler by the scons build system?
If answer to question 1 is yes, are these same flags then passed to
clang when YCM compiles the files? If so, is YCM compiling or more
technically processing the c++ files in the project to use for
semantic completion?
If answer to question 2 is yes, then I am guessing the flags I state in
the "flags" variable will not work for clang, as they are applicable to
g++. Should I do a conversion/mapping of the flags to clang?
Does YCM use clang to only front-end compile the files to produce the
AST to use for semantic completion?
Sorry about the naive questions, I am very new to YCM. Any help/guidance would be very appreciated.
Regards and thank you,
Ahmed.
The easiest way to get autocompletion working in vim with ycm is bear:
https://github.com/rizsotto/Bear
Install it and then just run:
bear scons
and you'll get your compilation database that makes ycm happy.
Related
The existing code is calling some sort of wx header file and my DEV C++ compiler just says there's no such file.
Code:
#include<wx/wx.h>
Compiler error:
[Error] wx/wx.h: No such file or directory
So my question is -
What is wx.h
How do I install it in my compiler so that I can use it?
Do I need to change my compiler or DEV C++ would do fine?
What is wx.h
It is the header file of a library. The GitHub project should have some instructions on how to fetch the dependencies and how to install them.
How do I install it in my compiler so that I can use it?
Normally you have to download the dependency, build it (following some instructions), and then you need to use the header in your project and link the library. The exact steps depend on each library and each compiler.
Do I need to change my compiler or DEV C++ would do fine?
In principle, no. Some libraries only work with some compilers, though.
Note that Dev-C++ is not a compiler, it is an IDE that comes with a port of GCC (as far as I know).
It seems that you are using WxWidgets framework but your compiler doesn't know where to find its headers, and apparently also libs which you would face with on a next step.
You, need to add to your compiler flags the output of wx-config --cxxflags. And also to your linker flags the output of wx-config --libs.
Assumption is of course that WxWidgets is installed on your PC
This is probably not possible, but I still want to ask. I'm using Clangd as an autocompletion engine for VSCode. It works great, but there is one problem.
The official Windows binaries of Clang rely on MSVC standard library headers. If MSVC is not installed, Clang and Clangd complain about missing headers.
There's a flag that makes Clang use MinGW's libstdc++ (--target=x86_64-w64-windows-gnu), which I have to include in compile_commands.json.
This solution works, but it would be nice to have sensible autocomplete even without compile_commands.json.
Is there a way I can tell Clangd to assume --target=x86_64-w64-windows-gnu if there is no compile_commands.json?
At some point after the question was asked, the VSCode Clangd extension started exposing the default flags to the config: "clangd.fallbackFlags": ["--target=x86_64-w64-windows-gnu"].
Is there a way I can tell Clangd to assume --target=x86_64-w64-windows-gnu if there is no compile_commands.json?
From clangd getting started:
compile_flags.txt
If all files in a project use the same build flags, you can put those
flags one-per-line in compile_flags.txt in your source root.
Clangd will assume the compile command is clang $FLAGS some_file.cc.
Creating this file by hand is a reasonable place to start if your
project is quite simple.
Just create compile_flags.txt file with --target=x86_64-w64-windows-gnu.
We are doing a C++ project for our uni and its final phase is passing the whole thing into a graphical interface using Qt.
We use Qt5.4 and g++-5. These values have been set in the QtCreator project configuration by selecting the appropriate compiler, g++-5, and also adding options in the *.pro file such as -std=c++14 and so on.
Nevertheless we are being stumped by an important issue. No matter what we try, when running qmake so as to auto-generate the precompiled files, in any Makefile generated by it, the compiler is ALWAYS set to g++ and not g++-5. We are at the moment obliged to after using qmake having to change by hand the compiler in the Makefile on our own, even though we have told it EVERYWHERE that we are using g++-5 and not the normal g++.
We have tried solutions like in this question: Using c++14
And also changing the compiler in the mkspecs of the Qt SDK.
Both have been to no avail and we still can't get the auto-generated Makefile to use g++-5 unless we change it by hand.
Is this a Qt issue or are we doing a step incorrectly?
Thanks in advance.
Sorry for all the bother.
It is solved now, I had linked my g++ compiler to g++-5 when I installed it ages ago but had forgotten (both g++ and g++-5 work on my pc, but they are the same) so it wasn't being an error, just my pc configuration getting in the way, thanks for the help though.
I have a code on my computer uses Petsc which depends on mpi. On my computer it works well. I put it on cluster, exported paths of gcc, Petsc and openmpi (although I was using mpich on my computer I hope openmpi will also work) to LD_LIBRARY_PATH and PATH. I also changed paths in makefile. Petsc, gcc, openmpi were all available on cluster so I did not configure anything. When I did make, compiler gave error:
fatal error: mpi.h: No such file or directory
I know I did not give complete information but I can tell more if needed. How can I make the Petsc to know where is mpi.h?
Typically, you should use mpicc (or mpicxx for C++) to compile instead of gcc (or g++ for C++). These commands are simple wrappers around gcc and g++ that simply add in the appropriate -I/path/to/mpi/includes and -L/path/to/mpi/libs automatically and should be included with your openmpi install. In the absence of that, simply add -I/path/to/mpi/includes in your command to compile the appropriate files. This tells the compiler where to look for the appropriate header files.
To answer the question. To prevent a C/C++ editor from showing errors as you tyoe in the "special code" just use:
#include </usr/include/mpi/mpi.h>
which seems to be a link -- but doing that turns off the errors in Netbeans editor so I can code without distraction.
Note: Using Ubuntu 18.04 Desktop as editing machine -- and testing run machine -- but I compile manually using mpic as noted previously.
sudo mpicc c_pi.c -o c_pi
and then...
mpiexec ./c_pi
hth
I switch between so many projects and IDEs a lot. They run each project with default options of IDE. For example
g++ test.cpp
I know make file can solve the problem. But it is not IDE friendly way. I am thinking if there is any way to impose option
-std=c++11
In the code rather than in calling g++.
The same problem with linker. I want to tell the linker in the code that I want to link to armadillo library
-larmadillo
Maybe setting a prepossessing command could solve the problem. Is there any solution for it?
Have you tried CMake? With this you can create compiler and IDE independent makefiles and then generate the makefiles/project files for the environment of your choise. You can freely script it so you can set certin swithces for gcc and other for vc++ or clang.
You can also use it if you want to create different build configurations.