Fedora Installing-liboqs
git clone https://github.com/open-quantum-safe/liboqs.git cd liboqs mkdir build cd build cmake ..
-DENABLE_STATIC=ON -DENABLE_SHARED=OFF # Static linking is often preferred for wallets
make -j $(nproc) sudo make install sudo ldconfig ,
AI
Okay, those commands are correct for building and installing liboqs (the Open Quantum
Safe library) with static linking. Let's break down what they do and some potential issues you
might encounter.
Explanation of the Commands:
1. git clone https://github.com/open-quantum-safe/liboqs.git:
○ This command uses git to clone (download) the liboqs repository from GitHub to
your local machine. It creates a directory named liboqs in your current directory
and downloads all the source code, history, and related files.
2. cd liboqs:
○ This command changes your current working directory to the liboqs directory that
was just created by the git clone command. This puts you "inside" the liboqs
source code tree.
3. mkdir build:
○ This command creates a new directory named buildinside the liboqs directory. It's a
common practice to create a separate build directory to keep the source code clean
and to avoid cluttering the source directory with build artifacts (object files, libraries,
executables, etc.).
4. cd build:
○ This command changes your current working directory to the build directory.
5. cmake .. -DENABLE_STATIC=ON -DENABLE_SHARED=OFF:
○ This is the most crucial command. It uses cmake to configure the build process for
liboqs.
○ cmake ..: This tells cmake to look for the CMakeLists.txt file (which describes how
to build the project) in the parent directory (i.e., the liboqsdirectory).
○ -DENABLE_STATIC=ON: This option tells cmake to enable building liboqs as a static
library. A static library is linked directly into your application during compilation,
making your application self-contained (doesn't require the liboqs shared library
to be present on the system where your application is deployed).
○ -DENABLE_SHARED=OFF: This option tells cmake to disable building liboqs as a shared
library. Shared libraries are loaded at runtime. Static linking is often preferred for wallet-type
applications because it reduces dependencies and simplifies deployment. 6. make -j $(nproc):
○ This command uses make to actually build the liboqslibrary.
○ -j $(nproc): This option tells make to use multiple threads or processes to build the
library in parallel. $(nproc) expands to the number of processor cores available on
your system, which can significantly speed up the build process.
7. sudo make install:
○ This command installs the built liboqs library and its header files to the system's
standard locations (e.g., /usr/local/lib, /usr/local/include). The sudo part
is important because installing to system directories usually requires
administrator privileges.8. sudo ldconfig:
○ This command updates the dynamic linker's cache. It's needed after installing new
shared libraries so the system knows where to find them. However, since you built
liboqs as a static library (and disabled shared library building), this command is
technically unnecessary in this specific case. It doesn't hurt to run it, though.
Potential Issues and Troubleshooting:
● Missing Dependencies: cmake might complain if you're missing dependencies required by
liboqs. The error messages will usually tell you what's missing. Go back and use dnf
install to install the necessary packages. Common dependencies include gcc, gcc-c++,
make, cmake, openssl-devel, and possibly others depending on the specific configuration.
● CMake Errors: Double-check that you've typed the cmakecommand correctly, especially the
paths and options. If cmake fails, it might be due to incorrect configuration options or a
problem with the CMakeLists.txt file itself.
● Permission Issues: If you forget to use sudo for make install, you'll likely get permission
errors.
● Compiler Errors: If make fails, it's usually because of errors in the C or C++ code. Carefully
examine the error messages to identify the source of the problem. This might require
debugging the liboqs source code.
● Incorrect Path: After installation, ensure that the compiler can find the liboqs header files
(e.g., <oqs/oqs.h>). If you're using a custom build system, you might need to add
/usr/local/include (or wherever you installed the headers) to your compiler's include
path. Similarly, for linking, you might need to add /usr/local/lib (or wherever you
installed the library) to your linker's library path and specify -loqs to link against the liboqs
library.
● Conflicts with Existing Libraries: If you have older versions of some libraries installed, there
might be conflicts during the build or linking process. Consider using a virtual environment or
container to isolate the build environment.
● Outdated liboqs Version: The liboqs project is actively developed. If you're using an older
version of the code, you might encounter issues. Try updating the repository by running git
pull inside the liboqs directory before building.
● Linking Issues: If you are linking dynamically, running sudo ldconfig might still be required.
Also ensure your code includes the correct library file when linking during compilation.
Example using GCC g++ main.cpp -o myprogram -loqs
Example Compilation and Linking:
Let's say you have a C++ file named myprogram.cpp that uses liboqs. After successfully
building and installing liboqs, you would compile and link it like this:
g++ myprogram.cpp -o myprogram -I/usr/local/include -L/usr/local/lib -loqs
-static
● g++ myprogram.cpp -o myprogram: This compiles myprogram.cpp and creates an executablenamed myprogram.
● -I/usr/local/include: This tells the compiler where to find the liboqs header files (the
include directory).
● -L/usr/local/lib: This tells the linker where to find the liboqs library file (the library
directory).
● -loqs: This tells the linker to link against the liboqs library (the -l option followed by the
library name without the libprefix or the .a or .so extension).
● -static: Forces static linking so the executable has all necessary dependencies
Important: Check Your Installation
After running sudo make install, verify the installation by checking if the liboqs header files are
present in /usr/local/include (or the appropriate include directory on your system) and if the
static library liboqs.a is present in /usr/local/lib (or the appropriate library directory). If these
files are not there, the installation was not successful, and you need to review the build process for
errors. By following these steps and addressing potential issues, you should be able to successfully
build and install liboqs on your Fedora Linux system. Good luck
