I have found several interesting links talking about a CPack generator for FreeBSD.
I would like to generate FreeBSD packages; however, whenever I attempt to generate TXZ archives (as directed by the instructions), the generated package isn't compatible with the pkg utility on FreeBSD. They miss the manifest file.
Obviously, CPack is generating raw archives, not pkg-ready archives. I assume I must be missing a step.
However, none of the links above talk about any such step.
Therefore,
How can I tell CPack to generate a FreeBSD-ready package?
(Original author of that code here)
So, there's two things in play here:
you need to be on FreeBSD (so that you have libpkg, which is needed to do the building)
you need to build the devel/cmake package with OPTIONS CPACK (which is not the default)
So:
cd /usr/ports/devel/cmake
make configure and select CPACK
make && make install
Then #Tsyvarev's comment will be the right answer. For the record, the support was deemed experimental, the library API unstable, and the pkg authors have asked me to re-vamp the code to use the current libpkg API so they can drop the old one. Time, though, is the limiting factor.
Related
I am learning CMake, and I feel hard to understand when I should use find_package.
For separate compilation, we need to let the compiler knows where to find the header file, and this could be done by target_include_directories. For linking, we need to let the linker knows where the implementation is, and this could be done by target_link_libraries. It seems like that is all we need to do to compile a project. Could anyone explain why and when we should use find_package?
If a package you intend allows for the use of find_package, you should use it. If a package comes with a working configuration script, it'll encourage you to use the library the way it's intended to be used likely come with a simple way to add include directories and dependencies required.
When is it possible to use find_package?
There needs to be either a configuration script (<PackageName>Config.cmake or packagename-config.cmake) that gets installed with the package or find script (Find<PackageName>.cmake). The latter one in some cases even comes with the cmake installation instead of the package installed, see CMake find modules.
Should you create missing scripts yourself?
There are several benefits in creating a package configuration script yourself, even if a package doesn't come with a existing configuration or find script:
The scripts separate the information about libraries from the logic used to create your own target. The use of the 2 commands find_package and target_link_libraries is concise and any logic you may need to collect and apply information like dependencies, include directories, minimal versions of the C++ standard to use, ect. would probably take up much more space in your CMakeLists.txt files thus making it harder to understand.
If makes library used easy to replace. Basically all it takes to go with a different version of the same package would be to modify CMAKE_PREFIX_PATH, CMAKE_MODULE_PATH or package-specific <PackageName>_ROOT variables. If you ever want to try out different versions of the same library, this is incredibly useful.
The logic is reuseable. If you need to use the same functionality in a different project, it takes little effort to reuse the same logic. Even if a library is only used within a single project, but in multiple places, the use of find_package can help keeping the logic for "importing" a lib close to its use (see also the first bullet point).
There can be multiple versions of the same library with automatic selection of applicable ones. Note that this requires the use of a version file, but this file allows you to specify, if a version of the package is suitable for the current project. This allows for the checking the target architecture, ect. This is helpful when cross compiling or when providing both 32 and 64 bit versions of a library on Windows: If a version file indicates a mismatch the search for a suitable version simply continues with different paths instead of failing fatally when considering the first mismatch.
You will probably find CMake's guide on using dependencies helpful. It describes find_package and alternatives, and when each one is relevant / useful. Here's an excerpt from the section on find_package (italics added):
A package needed by the project may already be built and available at some location on the user's system. That package might have also been built by CMake, or it could have used a different build system entirely. It might even just be a collection of files that didn't need to be built at all. CMake provides the find_package() command for these scenarios. It searches well-known locations, along with additional hints and paths provided by the project or user. It also supports package components and packages being optional. Result variables are provided to allow the project to customize its own behavior according to whether the package or specific components were found.
find_package requires that the package provide CMake support in the form of specific files that describe the package's contents to CMake. Some library authors provide this support (the most desirable scenario for you, the package consumer), some don't but are prominent enough that CMake itself comes with such files for those packages, or in the worst case, there is no CMake support at all, in which case you can either do something to get the either of the previous good outcomes, or perform some kludges to get the job done (ie. define the targets yourself in your project's CMake config).
When comparing different RPM files, I've noticed that not all of them expose the same header tags. So there must be some logic that activates/deactivates creation of some of them.
One example is the build time and host. I've stumbled upon two RPM specs. Neither mentions anything that looks at all like a specification or switch to provide the information. Still, one of them is generated with Build Time and Build Host fields, the other isn't (I am not permitted to post either one).
I am aware of the new _buildhost macro. The RPM version used to generate both is insufficient to use it. Both packages get created from a list of Sources, as far as I can see. The one that doesn't display the build information gets built using CMake/CPack, the other uses rpmbuild directly, that's the only information I have about serious difference.
Both are defined as Group: AddOn. So far, I haven't found any remotely definite resources about what groups are valid, or their meanings. Only thing I found was the list of deprecated groups in Fedora. I'd be more interested in a list of supported ones, but wasn't successful so far.
Resources I've found until now (omitting the pointless ones):
Max RPM Package Building Page, RedHat blog-ish tutorial, The RPM build guide, The actual RPM tags documentation, The RPM packaging guide
Unfortunately, none of the above provide the information I'm looking for.
"Give a man a fish" question: How can I suppress creation of Build Time or Build Host in rpm 4.11, be it in spec syntax or in usage of rpmbuild?
"Teach a man how to fish" question: Is there any documentation about what header tags get created with which settings?
You can use Mock for building rpm (recommended anyway). and use config_opts['hostname'] = 'my.own.hostname'.
Mock will call sethostname() in the chroot.
This is the only way how to do it AFAIK.
rpmbuild should honor SOURCE_DATE_EPOCH - but I never used it.
You can set environment variable using:
config_opts['environment']['SOURCE_DATE_EPOCH'] = 'foo'
I'm creating a library (called fmi2) which I intend to install on my local machine (via a package manager) and then link to with a bunch of other libraries.
I'll be providing a Findfmi2.cmake file so that I can call find_package(fmi2) from my other libraries, but where should this file be conventionally installed?
Here are some choices I've considered and their problems:
/usr/share/cmake-3.8/Modules/Findfmi2.cmake
Advantage: find_package(fmi2) will just work
Disadvantage: Only works for one version of cmake
/usr/share/cmake/Modules/Findfmi2.cmake
Advantage: Should work for any version of cmake
Disadvantage: This is not a default folder. We would need to add set(CMAKE_MODULES_PATH /usr/share/cmake/Modules) and this kills any portability.
${CMAKE_CURRENT_SOURCE_DIR}/cmake/Findfmi2.cmake
Advantage: Portable, just need to add set(CMAKE_MODULES_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake)
Disadvantage: Not system-wide. Need to manually add this file to each library that uses it. This duplicates files in my framework.
You are authoring content in CMake. You don't need a FindModule. That is designed to find external non-CMake outputs.
This Stackoverflow post from ruslo should help you understand the difference between find_package() module mode and config mode. It also answers your question about paths for FindModules, i.e. they are copied into your CMake project, not discovered system-wide, unless they are part of the official FindModules bundled with CMake in the "Modules" directory.
Modern CMake documentation now finally contains good examples to create a config mode package: cmake-packages
If you want explicit full examples, though using slightly older syntax for the config.cmake files, ruslo has more on Github.
I'd like to access a dynamic library using FFI features in the Ren-C Rebol branch. I understand this is possible by building with LibFFI support enabled. What steps do I need to take to enable this?
I mainly use OS X for development, though would also like to be able to build it for use with Linux.
(Note: This is probably the kind of information that should be added to the Wiki, as it is not so much a language question but the kind of thing that is subject to change over time. But, answerable, so...)
If you're using the GNU make method to build (where make -f makefile.boot generates a makefile for you) then you should find some lines in there like:
TO_OS_BASE?= TO_OSX
TO_OS_NAME?= TO_OSX_X64
OS_ID?= 0.2.40
BIN_SUFFIX=
RAPI_FLAGS= -D__LP64__ -DENDIAN_LITTLE -DHAS_LL_CONSTS -O1 ...
HOST_FLAGS= -DREB_EXE -D__LP64__ -DENDIAN_LITTLE ...
Modify the RAPI_FLAGS and HOST_FLAGS lines at the beginning to add -DHAVE_LIBFFI_AVAILABLE. That (-D)efines a preprocessor directive to tell the code it's okay to generate calls to FFI, because you have it available for linking later.
Now to tell it where to find include files. There's a line for includes that should look like:
INCL ?= .
I= -I$(INCL) -I$S/include/ -I$S/codecs/ ...
To the tail of that you need to add something that will look like -I/usr/local/opt/libffi/lib/libffi-3.0.13/include, or similar. The actual directory will depend on where you have libffi on your system. On the OSX system I'm looking at, that has two files in it, ffi.h and ffitarget.h.
(Note: I'm afraid I don't know how these files got on this computer. They didn't ship with the OS, so they came from...somewhere. I don't generally develop on OSX--nor for that matter do I use this FFI. You'll have to consult your local FFI-on-OSX website, or perhaps for support contact Atronix Engineering) who added the FFI features to Rebol.)
Then it's necessary to tell it where you have libffi on your system. You'll find a CLIB line that is likely just CLIB= -lm. You'd change this for example to:
CLIB= -L/usr/local/opt/libffi/lib -lm -lffi
-lffi Tells it to look for the ffi (-l)ibrary, and -lxxx means it assumes the name of the library will be libxxx[something]. -L/usr/local/opt/libffi/lib tells it where to look for it. You'll have to figure out where (if anywhere) you have libffi, and if not get it. If you had it, the directory would have contents something like:
libffi-3.0.13
libffi.6.dylib
libffi.a
libffi.dylib
pkgconfig
I mainly use OS X for development, though would also like to be able to build it for use with Linux.
On Linux it's similar but generally much easier to get the library, as easy as sudo apt-get install libffi-dev. Same step for the RFLAGS and CFLAGS, and it should take care of the location automatically... so you can add just -lffi to CLIB.
Old notes from me:
cat steps-for-lib-ffi-osx
Install libfffi via homebrew
brew install libffi
Add /use/include/libffi to the -I in the generated makefile
Add /usr/local/Cellar/libffi/3.0.13/lib/libffi.a to the OBJS in the
generated makefile
The version 3.0.13 may vary
I'm trying to convert our build system at work over to cmake and have run into an interesting problem with the RPMs that it generates (via cpack): It automatically adds all of the dependencies that it thinks your RPM has to its list of required libraries.
In general, that's great, but in my case, it's catastrophic. Unfortunately, the development packages that we build end up getting installed with one our home-grown tool that uses rpm to install them in a separate RPM database from the system one. It's stupid, but I can't change it. What this means is that all of the system libraries that any normal library will rely on (like libc or libpthread) aren't in the RPM database that is being used with our development packages. So, if an RPM for one of our development packages lists system libraries as being required, then we can't install it, as rpm will think that they're not installed (since they're listed in the normal database rather than the one that it's being told to use when installing our packages). Our current build stuff handles this just fine, because it doesn't list any system libraries as dependencies in the RPMs, but cpack automatically populates the RPM's list of required libraries and puts the system libraries in there. I need a way to stop it from doing so.
I tried setting CPACK_RPM_PACKAGE_REQUIRES to "", but that has no effect. The RPM cpack generates still ends up with the system libraries listed as being required. All I can think of doing at this point is to copy the RPM cpack generator and hack it up to do what I want and use that instead of the standard one, but I'd prefer to avoid that. Does anyone have any idea how I could get cpack to stop populating the RPM with required libraries?
See bottom of
http://www.rpm.org/max-rpm/s1-rpm-depend-auto-depend.html
The autoreqprov Tag — Disable Automatic Dependency Processing
There may be times when RPM's automatic dependency processing is not desired. In these cases, the autoreqprov tag may be used to disable it. This tag takes a yes/no or 0/1 value. For example, to disable automatic dependency processing, the following line may be used:
AutoReqProv: no
EDIT:
In order to set this in cmake, you need to do set(CPACK_RPM_PACKAGE_AUTOREQPROV " no"). The extra space seems to be required in front of (or behind) the no in order for it to work. It seems that the RPM module for cpack has a bug which makes it so that it won't let you set some its variables to anything shorter than 3 characters long.
To add to Mark Lakata's answer above, there's a snapshot of the "Maximum RPM" doc
http://www.rpm.org/max-rpm-snapshot/s1-rpm-depend-auto-depend.html
that also adds:
The autoreq and autoprov tags can be used to disable automatic processing of requirements or "provides" only, respectively.
And at least with my version of CPackRPM, there seems to be similar variables you can set e.g.
set(CPACK_RPM_PACKAGE_AUTOREQ " no")
to only disable the automatic dependency processing of 'Requires'.