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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/intro.cli | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/doc/intro.cli b/doc/intro.cli index a90a3ae..8d98c22 100644 --- a/doc/intro.cli +++ b/doc/intro.cli @@ -138,6 +138,9 @@ our case it is an executable implemented in C++. a \c{git} repository and generates suitable \c{.gitignore} files (pass \c{-s\ none} if you don't want that).| +\N|Note to Windows users: the \c{build2-baseutils} package includes core +\c{git} utilities that are sufficient for the \c{bdep} functionality.| + Let's take a look inside our new project: \ @@ -979,6 +982,125 @@ immediate (\c{sync\ -ui}), or even upgrade immediate and patch the rest (\c{sync\ -ui} followed by \c{sync\ -pr}). +\h#guide-unpackaged-deps|Unpackaged Dependencies| + +Generally, we will have a much better time if all our dependencies come as +\c{build2} packages. Unfortunately, this won't always be the case in the real +world and some libraries that you may need will use other build systems. + +\N|There is also the opposite problem: you may want to consume a library that +uses \c{build2} in a project that uses a different build system. For that +refer to \l{#guide-consume-pkg Package Consumption}.| + +The standard way to consume such unpackaged libraries is to install them (not +necessarily into a system-wide location like \c{/usr/local}) so that we have +a single directory with their headers and a single directory with their +libraries. We can then configure our builds to use these directories when +searching for imported libraries. + +\N|Needless to say, none of the \c{build2} dependency management mechanisms +such as version constraints or upgrade/downgrade will work on such unpackaged +libraries. You will have to manage all these yourself manually.| + +Let's see how this all works in an example. Say, we want to use \c{libextra} +that uses a different build system in our \c{hello} project. The first step +is to manually build and install this library for each build configuration +that we have. For example, we can install all such unpackaged libraries into +\c{unpkg-gcc} and \c{unpkg-clang}, next to our \c{hello-gcc} and +\c{hello-clang} build configurations: + +\ +$ ls +hello/ +hello-gcc/ +unpkg-gcc/ +hello-clang/ +unpkg-clang/ +\ + +\N|If you would like to try this out but don't have a suitable \c{libextra}, +you can create and install one with these commands: + +\ +$ bdep new -t lib -l c++ libextra -C libextra-gcc cc config.cxx=g++ +$ b install: libextra-gcc/ config.install.root=/tmp/unpkg-gcc +\ + +| + +If we look inside one of these \c{unpkg-*} directories, we should see +something like this: + +\ +$ tree unpkg-gcc +unpkg-gcc +├── include +│ └── libextra +│ └── extra.hxx +└── lib + ├── libextra.a + ├── libextra.so + └── pkgconfig + └── libextra.pc +\ + +Notice that \c{libextra.pc} \- it's a \cb{pkg-config(1)} file that contains +any extra compile and link options that may be necessary to consume this +library. This is the \i{de facto} standard for build systems to communicate +library build information to each other and is today supported by most +commonly used implementations. Speaking of \c{build2}, it both recognizes +\c{.pc} files when consuming third-party libraries and automatically produces +them when installing its own. + +\N|While this may all seem foreign to Windows users, there is nothing +platform-specific about this approach, including support for \c{pkg-config}, +which, at least in case of \c{build2}, works equally well on Windows.| + +Next, we create a build configuration and configure it to use one of these +\c{unpkg-*} directories (replace \c{...} with the absolute path): + +\ +$ bdep init -C ../hello-gcc @gcc cc config.cxx=g++ \ + config.cc.poptions=-I.../unpkg-gcc/include \ + config.cc.loptions=-L.../unpkg-gcc/lib +\ + +\N|If using Visual Studio, replace \c{-I} with \c{/I} and \c{-L} with +\c{/LIBPATH:}.| + +Alternatively, if you want to reconfigure one of the existing build +configurations, then simply edit the \c{build/config.build} file (that is, +\c{hello-gcc/build/config.build} in our case) and adjust the \c{poptions} and +\c{loptions} values. Or you can use the build system directly to reconfigure +the build configuration (see \l{b(1)} for details): + +\ +b configure: ../hello-gcc/ \ + config.cc.poptions+=-I.../unpkg-gcc/include \ + config.cc.loptions+=-L.../unpkg-gcc/lib +\ + +\N|If all the unpackaged libraries included \c{.pc} files, then the \c{-L} +alone would have been sufficient. However, it doesn't hurt to also add +\c{-I}, for good measure.| + +Once this is done, adjust your \c{buildfile} to import the library: + +\ +import libs += libextra%lib{extra} +\ + +And your source code to use it: + +\ +#include <libextra/extra.hxx> +\ + +\N|Notice that we don't add the corresponding \c{depends} value to the +project's \c{manifest} since this library is not a package. However, it is a +good idea to instead add a \l{bpkg#manifest-package-requires \c{requires}} +entry as a documentation to users of our project.| + \h#guide-versioning-releasing|Versioning and Release Management| Let's now discuss versioning and release management and, yes, that @@ -1244,6 +1366,11 @@ users of our project get them? While they could clone the repository and use consumption workflow. For consumption it is much easier to use the package dependency manager, \l{bpkg(1)}, directly. +\N|Note that this approach also works for libraries in case you wish to use +them in a project with a build system other than \c{build2}. See +\l{#guide-unpackaged-deps Unpackaged Dependencies} for background on +cross-build system library consumption.| + First, we create a suitable build configuration with the \l{bpkg-cfg-create(1)} command. We can use the same place for building all our tools so let's call the directory \c{tools}. Seeing that we are only @@ -1387,4 +1514,5 @@ purged libhello purged libformat purged libprint \ + " |