How to use C library installed with vcpkg on linux? - c

Question

I'm trying to install libwebsockets C library with vcpkg according to the instruction. And don't understand something.
OS - Ubuntu 20.04
git clone https://github.com/microsoft/vcpkg.git
cd vcpkg
./bootstrap-vcpkg.sh
./vcpkg install [library-name]
Library is installed and what to do next? How to compile test files with the library?
The question is more about how to use vcpkg on linux.
You can give an example of another library installed with vcpkg.

Answer 1

vcpkg is a C/C++ package manager, it is very necessary in windows.
However, in ubuntu, itself provides a very complete package management mechanism.
Therefore, even if you are building a cross platform software system, do not use vcpkg in ubuntu :)
You can try this:
$> sudo apt install libwebsockets-dev
In this way, the libwebsockets header files and library files you need have been installed and can be used directly.

Answer 2

Here is another example:
I want to install gtkmm4 in ubuntu 20.04 LTS, since gtkmm4 is not available for apt download I'm installing it with vcpkg.
for simplification, I'm setting VCPKG_DIR to the vcpkg directory I cloned.
export VCPKG_DIR=/path/to/vckpg
Then for a C++ program, you can write CMake file like below
PROJECT(gtkmmtest)
cmake_minimum_required(VERSION 3.10)
set(VCPKG_DIR $ENV{VCPKG_DIR})
include(${VCPKG_DIR}/scripts/buildsystems/vcpkg.cmake) # --> important
# Use the package PkgConfig to detect GTK+ headers/library files
FIND_PACKAGE(PkgConfig REQUIRED)
FIND_PACKAGE(Threads REQUIRED)
pkg_check_modules(GTK4 REQUIRED gtk4)
PKG_CHECK_MODULES(GTKMM gtkmm-4.0)
include_directories(${GTK4_INCLUDE_DIRS})
include_directories(${GTKMM_INCLUDE_DIRS})
link_directories(${VCPKG_DIR}/packages/gtk_x64-linux/lib)
link_directories(${GTK4_LIBRARY_DIRS})
add_definitions(${GTK4_CFLAGS_OTHER})
target_link_libraries(${GTKMMTEST} PRIVATE ${GTK4_LIBRARIES} ${GTKMM_LIBRARIES} pthread)
Complete CMake file can be found here
You can still use the the standard include_directories and link_directories if there is no PkgConfig avilable.
eg:
include_directories(${VCPKG_DIR}/packages/gtkmm_x64-linux/include/gtkmm-4.0/)

Answer 3

Library is installed and what to do next? How to compile test files with the library?
The question is more about how to use vcpkg on linux.
The answer to this question really depends on your buildsystem and the port/library you want to use and not the platform itself.
In the case of libwebsockets libwebsockets-config.cmake get installed so you could use CMake and do a find_package(libwebsockets CONFIG REQUIRED) to get the imported targets the port exports within LibwebsocketsTargets.cmake. Of course this requires setting CMAKE_TOOLCHAIN_FILE to the vcpkg toolchain (<vcpkg_root>/scripts/buildsystems/vcpkg.cmake) or including it before the first project() in your CMakeLists.txt (more details are mentioned in the vcpkg docs which you hopefully read....)
Other libraries/ports might export *.pc files. For these FindPkgConfig.cmake can be used directly (see CMake docs) or you can setup PKG_CONFIG_PATH and prepend <vcpkg_root>/installed/<triplet (here probably: x64-linux)>/(debug/)lib/pkgconfig for other buildsystems like autotools or manual makefiles etc.
In the end how to use vcpkg or more precisly the libraries from it depends on what buildsystem you intend to use.