I want to use this library https://github.com/troldal/OpenXLSX on my linux machine. How do I install or use libraries found on Gitub?
Also how do I know what compiler flags to use?
The library you linked to is built using CMake (can be seen by the existence of a CMakeLists.txt file).
So you'd have to
download the source code (git clone https://github.com/troldal/OpenXLSX.git on Linux/Mac or using git bash on Windows)
generate the build system for your compiler (mkdir build; cd build; cmake .. on Linux/Mac)
build the library (make on Linux/Mac)
Once you have built the library, generally there is an include directory and a lib directory (sometimes also named bin). If you are compiling directly using g++ or clang++, you'll have to add the include directory with the -I flag and the built library file in lib or bin with the -l flag:
g++ -Ipath/to/include -l/path/to/lib/libOpenXLSX.so your_sources.cpp
If you are using CMake or an IDE with its own build system, you'll have to add those two paths according to the documentation of that build system (see target_link_libraries for CMake for example).
CMake sometimes also generates "install" commands for built library. When you install the libraries, the headers and library will be copied to your global include path, so you won't need to specify the paths in your compile command anymore: g++ -lOpenXLSX your_sources.cpp.
Use the git clone command to download the library these two questions already answered would probably help you the most:
And in regards to flags you would use the -I flag.
How to use Libraries
C++ Link external libraries
Related
The issue
I am trying to use the execution policies in the standard algorithm library. However, when I try to compile I get the following error message
c:\mingw\lib\gcc\mingw32\9.2.0\include\c++\pstl\parallel_backend_tbb.h:19:10: fatal error: tbb/blocked_range.h: No such file or directory
After looking at various other related questions such as this or this, I understand that the execution library depends upon a software called tbb. Moreover in order to compile code which uses <execution> one has to manually link to tbb. My issue is precisely with how to download and link tbb to a script that uses <execution>.
I believe I have some serious gaps in my understanding in terms of how one downloads the correct files and then links to them. I will first make a list with my understanding of the linking process and then I will explain what I have tried to fix the issue. I have chosen this format so that it is faster for the one to answer my question to point at the issue at fault. I will attempt to keep this as concise as possible.
My understanding
Code is organized in header and cpp files, where the former usually only contain the interface to the software and the later the implementation
The cpp files can be pre-compiled and grouped into a single library file
For a user to then use the library, they have to #include the header/s in their script and also tell the compiler where the header files as well as the library file, are located
This can be done with the -I for the headers and -L, -l for the library file
-L provides the location of the library files, the -l specifies which libraries to use
What I tried
The script I try to compile is:
#include <execution>
int main() {
std::execution::par;
return 0;
}
with
g++ script.cpp -o out -I C:(path to the headers) -L C:(path to the library) -l (name of library) -std=c++17
I should also mention I am trying to do this on Windows 10
1st attempt
I had a particularly hard time understanding where to find the header and library files for tbb.
In the Intel getting started with TBB webpage, this github repository is listed as "TBB being available at". As I am used to header-only libraries I thought everything would be in the include directory but no .dll files where there. It is now my understanding that I have to compile the DLLs myself for my specific system which makes sense. I followed the following process using cmake:
# Do our experiments in /tmp
cd /tmp
# Clone oneTBB repository
git clone https://github.com/oneapi-src/oneTBB.git
cd oneTBB
# Create binary directory for out-of-source build
mkdir build && cd build
# Configure: customize CMAKE_INSTALL_PREFIX and disable TBB_TEST to avoid tests build
cmake -DCMAKE_INSTALL_PREFIX=/tmp/my_installed_onetbb -DTBB_TEST=OFF ..
# Build
cmake --build
# Install
cmake --install .
# Well done! Your installed oneTBB is in /tmp/my_installed_onetbb
However at the cmake --build step, cmake does not accept the command but requests more options. One of them is the dir option, which for which I made another directory and supplied it but then the error message Error: could not load cache printed out.
In any case, some files had been created so I searched for the .dll file but could not find it.
2nd attempt
I downloaded the Intel oneAPI Base Toolkit as is suggested here. After the installation at ../Program Files (x86)/Intel/oneAPI I found the specific tbb tool at C:\Program Files (x86)\Intel\oneAPI\tbb and I used this address for the -I and -L flags but initial error message persists.
I also copied the directory C:\Program Files (x86)\Intel\oneAPI\tbb\2021.6.0 to the local directory of the script so I could link with -flag tbb\2021.6.0 but no luck
Many thanks
Yes you were correct.
By using the package mingw-w64-tbb. You can use -ltbb12 instead of -ltbb. As the library files are related to ltbb12.
For using -ltbb option, you should set the Intel oneAPI environment. It can be used by downloading Intel oneAPI Base Toolkit.You can set the environment by sourcing setvars.sh file using the below command.
source /opt/intel/oneapi/setvars.sh
I have found this library https://github.com/embeddedmz/ftpclient-cpp on GitHub but how to install it on Linux(Ubuntu) is quite obscure.
You will need CMake to generate a makefile for the static library or
to build the tests/code coverage program. Also make sure you have
libcurl and Google Test installed.
You can follow this script
https://gist.github.com/fideloper/f72997d2e2c9fbe66459 to install
libcurl.
This tutorial will help you installing properly Google Test on Ubuntu:
https://www.eriksmistad.no/getting-started-with-google-test-on-ubuntu/
The CMake script located in the tree will produce Makefiles for the
creation of the static library and for the unit tests program.
To create a debug static library and a test binary, change directory
to the one containing the first CMakeLists.txt and :
mkdir build
cd build
cmake .. -DCMAKE_BUILD_TYPE:STRING=Debug
make
It is not clear to me what "to the one containing the first CMakeLists.txt" refers to. Is it the one in the Gtest? The one in Curl? Or What?
After trying both (the Cmake in Gtest and Curl) I still get the error: "No such file or directory" while trying to #include "FTPClient.h" .
UPDATE:
Listing what I am doing:
I did git clone https://github.com/embeddedmz/ftpclient-cpp.git then made the build folder, navigate into it, I tried cmake .. -DCMAKE_BUILD_TYPE:STRING=Debug (this is the literal command I inserted) and I get
Cmake Error at CmakeLists.txt: 27 (add_subdirectory): add_subdirectory given source "TestFTP" which is not an existing directory
So what is wrong so far?
After you build the library, there will be a libftpclient.a generated in your build tree.
You can install it to your system as follows:
In this case, copy libftpclient.a to /usr/local/lib and the two header files in FTP to /usr/local/include.
You should then be able to include the header files by adding the -I/usr/local/include flag and link by adding -L/usr/local/lib -lftpclient.
I'm trying to build wxWidgets library into a custom path on a Fedora 27 operative system.
I achieved the wx-config file path recognition and works with the cmake execution. Also, I load libraries and include dirs based on modified wxWidgets finder cmake file that sets thewx-config custom path successfully.
But cmake does not load my wxWidgets configuration. I mean, wx_gtk2u_jpeg-3.1 builded lib could not be founded (suposed to be /usr/lib/libwx_gtk2u_jpeg-3.1.so). I need jpeg dependency from wxWidgets for my project.
I'm sure that problem is not about cmake files. However, the problem is wxWidgets compilation because cmake can found the other builded dependencies into /usr/lib/
I actually installed the libjpeg-turbo-devel package that includes the libjpeg.h needed for wxWidgets building without success of libwx_gtk2u_jpeg-3.1.so creation.
The weirdest part is that $ wx-config --libs shows the wx_gtk2u_jpeg-3.1 lib to be linked and the hint paths that it should be founded.
wxWidgets commands for building:
$ ./configure --with-libjpeg=builtin --with-libpng=builtin --with-libtiff=builtin --with-zlib=builtin --with-expat=builtin --enable-webviewwebkit=no --prefix=/opt/cpp_dependencies/2018Q1/usr'
$ make -j 4
$ make install
You can check out my cmake files, the cmake output and wxWidgets building output in order to reproducing it: https://gist.github.com/jjalvarezl/b70accae269ef56c56010bedf157c27f
You can see line 1543 of wxWidgets building output file that jpeg library is buildin, and, 1564 of same file, the make install command that installs all libwx_<lib_name>.so libraries into final /usr/lib path. Anyway, no one contains the needed library.
Please show the exact error message, as it's not clear what the actual problem is. What I can say, is that the different built-in versions of 3rd party libraries, such as libjpeg, are always static libraries, even when wxWidgets themselves are shared. I.e. you're never going to have libwx_gtk2u_jpeg-3.1.so, only .a.
I'd also strongly recommend using system versions of the 3rd party libraries under Unix systems. This means that your wxWidgets applications will get security updates from your OS vendor and you don't risk running into any incompatibilities due to using 2 different versions of the same library in your application.
I am trying to build libtorrent (http://www.libtorrent.org/) using the provided jamfile. If I try to build it in its vanilla state everything goes well. I am then building using this command:
bjam msvc-12.0 boost=source
However I want to build it with OpenSSL which there seem to be support for. This is where I run into problems. Most likely because it is the first time I use Bjam (actually anything else than make files). I now try to run the following command:
bjam msvc-12.0 boost=source encryption=openssl
Now the compiler starts to complain about not finding the OpenSSL include files.
So I guess I have to include this path in the JAM file. But I have no idea where.
I also tried to add the path into the INCLUDE environment varaible in windows but that doesn't seem to be picked up by BJAM or msvc. Any suggestions?
My understanding of how this is normally done on windows is by installing libraries and headers into visual studio's include and lib folders.
(That's how I install openssl on windows at least).
The jamfile is also supposed to pick up CXXFLAGS and LDFLAGS environment variables, which you could use to introduce the library- and include paths. However, it only does this when boost=system is specified, i.e. you're building against "system" boost libraries instead of from source.
I am trying to use CMake in order to compile opencv.
I am reading the tutorial but can't understand what is CMakeLists files and how is it connected to the gui of CMake?
Also couldn't understand what are makefiles, are they the same is CMakeLists?
And which file is it which I in the end open with visual-studio?
I don't know about Windows (never used it), but on a Linux system you just have to create a build directory (in the top source directory)
mkdir build-dir
go inside it
cd build-dir
then run cmake and point to the parent directory
cmake ..
and finally run make
make
Notice that make and cmake are different programs. cmake is a Makefile generator, and the make utility is governed by a Makefile textual file. See cmake & make wikipedia pages.
NB: On Windows, cmake might operate so could need to be used differently. You'll need to read the documentation (like I did for Linux)
CMake takes a CMakeList file, and outputs it to a platform-specific build format, e.g. a Makefile, Visual Studio, etc.
You run CMake on the CMakeList first. If you're on Visual Studio, you can then load the output project/solution.
Yes, cmake and make are different programs. cmake is (on Linux) a Makefile generator (and Makefile-s are the files driving the make utility). There are other Makefile generators (in particular configure and autoconf etc...). And you can find other build automation programs (e.g. ninja).
CMake (Cross platform make) is a build system generator. It doesn't build your source, instead, generates what a build system needs: the build scripts. Doing so you don't need to write or maintain platform specific build files. CMake uses relatively high level CMake language which usually written in CMakeLists.txt files. Your general workflow when consuming third party libraries usually boils down the following commands:
cmake -S thelibrary -B build
cmake --build build
cmake --install build
The first line known as configuration step, this generates the build files on your system. -S(ource) is the library source, and -B(uild) folder. CMake falls back to generate build according to your system. it will be MSBuild on Windows, GNU Makefiles on Linux. You can specify the build using -G(enerator) paramater, like:
cmake -G Ninja -S libSource -B build
end of the this step, generates build scripts, like Makefile, *.sln files etc. on build directory.
The second line invokes the actual build command, it's like invoking make on the build folder.
The third line install the library. If you're on Windows, you can quickly open generated project by, cmake --open build.
Now you can use the installed library on your project with configured by CMake, writing your own CMakeLists.txt file. To do so, you'll need to create a your target and find the package you installed using find_package command, which will export the library target names, and link them against your own target.
Cmake from Windows terminal:
mkdir build
cd build/
cmake ..
cmake --build . --config Release
./Release/main.exe
Regarding CMake 3.13.3, platform Windows, and IDE Visual Studio 2017, I suggest this guide. In brief I suggest:
1. Download cmake > unzip it > execute it.
2. As example download GLFW > unzip it > create inside folder Build.
3. In cmake Browse "Source" > Browse "Build" > Configure and Generate.
4. In Visual Studio 2017 Build your Solution.
5. Get the binaries.
Regards.