I'm trying to do a static build for an open-source project and I'm getting lots of errors while I try to build it.
How do I find the correct version of a library that the project is using?
I also tried to read the Makefile but I couldn't understand much from it. So is there any workaround or anything like that which makes the work easier?
AFAIK there is no way to find it out. It's not just the version. Many libraries can be built with different flags. You have to know the supported versions and necessary flags. For this purpose package managers were invented. Each package has meta information describing the dependencies.
Someone wrote a code using a library. If you want to use the code you have to use a compatible library. You can't find it out from the code. You can ask the developer, read the documentation or look into the package description. If you can't find a documentation of the dependencies you can try different versions and flags. This can cause crashes, undefined behavior or it works if you're lucky and you found a compatible version.
Related
I'm currently working on a project with C++17 and I have trying to make use of certain libraries (such as variant and optional). However, my IDE cannot find these (I'm using CLion). What would be the best way to debug this issue? I want to know if I truly do not have these installed (although they are part of the STD Library so I would think this unlikely) or if there is an issue with my editor...
I am currently working on a masters project and I am desperately trying to compile some C++ code on my mac (macOS High Sierra 10.13.3 using Xcode) so I can develop the program at home. The Program is a set of files used for performing integrals on a bunch of different data... it uses headers from the boost library and also alglib. This all works fine on Windows machines running visual studios.
The issue I have is that when I include boost (which was installed via homebrew to usr/local/) into the search paths in the project build settings I get all sorts of semantic and linker issues.
I have searched this for a while and tried to implement a few potential fixes. I have tried:
Compiling with different C++ dialects and and standard libraries (libc++ and libstdc++).
Uninstalling/reinstalling boost.
Removing suggested header files and libraries from 'usr/local' suggested by brew doctor.
and implementing all sorts of other random permutations of settings that I felt could be issued.
The number of errors and warnings may change using different build settings however semantic issues persist and I am running out of ideas for how to proceed. It is really important I get this working and any insight would be appreciated.
From my reading about and attempting to troubleshoot I get the idea that it is some kind of linking issue between the boost library and the standard c++ libraries, but I have little experience with semantic issues as in the past I have been lucky enough that things just worked! Perhaps my MacBook may just have too much going on and needs some housecleaning to stop confusing the compiler, but regardless if anyone can help me fix this issue I would be eternally grateful!
I understand I haven't provided much detail here but if any information would be useful I'm happy to send screenshots.
link to errors image
In C++03 ifstream did not have a constructor that accepts std::string.
Such a constructor was added in C++11. The same holds for std::stod: it exists since C++11.
So you have to compile with -std=c++11 option.
I'm trying to teach myself C++ programming. The C++ is the easy part. Some patience and good reference material goes a long way. Including and linking against libraries is the hard part. The instructions provided usually assume some knowledge which I don't have and don't know how to aquire without painfully slow trial and error.
The latest concrete example is http://cpp-netlib.org/
I've spent the whole afternoon trying to get it to work and I still don't even an idea why it's not working.
How can I learn this skill from the ground up?
Is it it normal to have such enormous difficulties learning how to do this?
Well, the principle is pretty much always the same for any C++ compiler (the option flags mentioned are quite standard but might differ for particular compilers):
Install a library you want to use in your system (this may include a step to compile this library with your particular compiler toolchain).
Setup the include paths to be used for this library using the -I option
Use the headers of the library API in your code (#include <libheader.h>)
Setup the library paths to be used for this library using the -L option, tell the linker which libraries to link using -l<extra>, where extra should refer to some file named lib<extra>.a or lib<extra>.lib
Things to note:
Third party libraries might depend on further libraries you'd also need to install (compile with the same toolchain as your target uses)
On Windows using the MS Visual Studio (Express) toolchain you'll need to take care choosing the right library versions that are compliant with the 'threading model' and in general 'debug' / 'non-debug' library versions.
An (appropriate and useful) IDE will usually let you choose the toolchain (MinGW GCC, MS VS compiler, LLVM, etc.) on project setup, and offer some properties dialog to set these options.
What's necessary to setup for the toolchain, 3rd party libraries, IDE and OS you're using is a bit different learning curve and depends on what you want to use in particular.
I have just downloaded the boost libraries from the boost website and extracted them to my desktop. I was hoping to just have a quick look at them and have them installed on my machine and perhaps use them in the future when I am more accustomed to C++.
When I extracted it, I was confused with all of the extracted files. There is all of the headers in the boost directory but tutorials mention running bootstrap.bat (I'm using Windows).
So I am asking this: do I simply extract the headers to my compilers include directory like normal to get boost up and running or do I need to do something else?
As I understand it from searching about, apparently "most" of boost is just templates and can be used simply by including the headers, but what about the rest?
Am I totally barking up the wrong tree?
Thanks for any help
Since you mentioned you run Windows, take a look at this automated installer:
► http://www.boostpro.com/download/
Also, some general advice:
do I simply extract the headers to my compilers include directory
No! Do not pollute your compiler's includes with third-party includes; make a separate directory specifically for a particular library. You'll then need to tell your specific IDE in what directory it can find the library headers.
I usually use boostpro's installer, it is less work. I vaguely remember having to set up the BOOST_ROOT environment variable on one of my systems to use it.
The libraries that contained compiled source should be included in the installer.
If you don't use the installer (or don't set up your build correctly), and try to use the libraries that need it you will likely get some linker errors when you try and compile your program. Usually if you take those linker errors and plop them in google it tells you pretty quick which libraries you need to include in your build system. I use CMake for that and have been very happy..
Just add the root boost directory to include paths of your compiler/IDE (so if you have Boost extracted to C:\Boost, the compiler will use that path, not C:\Boost\boost).
Don't do any copying of the boost folder to your compiler's include directory, because it may make upgrading Boost harder in the future.
Also if you plan to use any of boost's compiled libraries, add Boost's lib directory to compiler's library search paths. Configuring the compiling step is a matter of putting the right toolset parameter to boost's build tool. If you have your command line environment configured properly, bootstrap should run and compile the builder without any problems, and the Boost builder should properly detect your toolset, so no parameters will be necessary.
As you do such configuration only once every time you do a clean install of your favorite compiler, it's not as hard or daunting as it seems.
I am trying to make my autotools project in C++ link against library, that originates as C library (libsomelib.so), but also has bindings to c++ (libsomelib++.so). I ma trying to use PKG_CHECK_MODULES to check if this package is installed, and use autotools to link against it. However both libs come in one package (c++ version requires configure flag), and have only one .pc file, in which independently of configuration settings there is only line
Libs: -L${libdir} -lsomelib
without any mentioning of ++ version. There is also no separate ++.pc file that i noticed at other programs. Therefore automatic linking against ++ version is impossible. I thought about manually adding -lsomelib++ to linking flags, but that's rather ugly (and it will not work if somebody compiled it without --with-cxx flag). I could also test for it's existence by AC_SEARCH_LIBS, but since it's C++ library it's not so straightforward.
Is missing ++.pc file mistake of package distributor or is it some deeper idea, and i don't know how to use it?
If somebody is really qurious i will say that package in question is ossp-uuid.
Yes, the missing ++.pc usually hints towards an omission on behalf of the packager.
BTW: If simple (DCE) UUIDs are sufficient, you could consider e2fsprogs/util-linux's libuuid (in case you run this OS).