How to manually postprocess CMake target during installation? - installation

I am working on a library that provides gdb pretty-printers. They could be automatically located by including the .debug_gdb_scripts section in the generated binary. For binaries inside build, I would like this section to point to the pretty-printer inside the source tree. For installed binaries, I would like to either strip this specific section only, or install the pretty-printer as well and change the reference to its installed location.
Is there builtin functionality in CMake or a simple solution to postprocess the installed binary?

Related

Finding vcpkg packages that don't have `find_package` documentation

When you install many packages through vcpkg (such as vcpkg install cairo), at the end of this process, you are told what find_package and target_link_libraries CMake commands to use in order to link to the package that was installed. And this works fine; you can even re-execute the install command to see these CMake commands again.
However, some packages installed through vcpkg don't have these. After installing Pango for example, there is no list of CMake commands to actually use the library. I found the target CMake file for find_package in several of the vcpkg package directories, but the Pango directory has no CMake file for the package.
For some reason, example code using Pango can still compile (ie: it can find Pango's headers), but it fails to link due to not linking to the right libraries.
So how is this supposed to work? Do I have to list the include directories, library directories, and library files through a variety of CMake interfaces for Pango? Or is there some alternative inclusion mechanism that takes care of the details like most other vcpkg packages?
Note that I'm using Visual Studio 2019's built-in CMake functionality to try to build with these.
find_package finds a particular kind of .cmake file that is usually shipped with vcpkg packages. These .cmake files do the work of setting include directories and libraries to link with.
As such, if a vcpkg package does not include such a file, you will need to essentially do the work that the file would have done. Fortunately, CMake and vcpkg know where the headers and library build files are for the various configurations. What you need to do is find those directories and libraries, then add them to your project (along with any other special compiler options that the package requires, which requires some familiarity with the package).
To find the include directory containing a library's header, use find_path to set a variable, giving it the name of a header file to search for. For example:
find_path(PANGO_INCLUDE_DIR pango/pango.h)
This header directory can then be set as part of the include path:
target_include_directories(project_name_here PRIVATE ${PANGO_INCLUDE_DIR})
Libraries are a bit harder, since you have to track down the full name (minus extensions) of the actual library. And if the package involves multiple libraries, you need to track down all of those which are applicable to you.
Given the name of a library or libraries of interest, you can find them one at a time with find_library, setting those libraries into variables:
find_library(PANGO_LIBRARY pango-1.0)
find_library(PANGOCAIRO_LIBRARY pangocairo-1.0)
You can then link with those libraries via target_link_libraries:
target_link_libraries(cairo_vcpkg PRIVATE
...
${PANGO_LIBRARY}
${PANGOCAIRO_LIBRARY}
)
Indeed, some packages installed via vcpkg do not export a .cmake file like Pango for you and SDL for me.
I want to clarify that I have been trying to use vcpkg for two days, I share with you the cmakelist.txt that I use on my side so that SDL works as if I had used find_package (SDL Required)
cmake_minimum_required(VERSION 3.16)
project(xxxx)
### Specify the C++ standard ###
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED True)
set(CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/CMake)
### To find and use SDL ###
# find path of include and lib
find_path(SDL_INCLUDE_DIR SDL/SDL.h)
find_library(SDL_LIBRARY SDL)
# find pat of manual-link library
set (LIBRARIES_TO_LINK C:/dev/vcpkg/installed:/x64-windows/lib/manual-link)
find_library(SDL1_TEST SDLmain HINTS ${LIBRARIES_TO_LINK})
....

Xcode use different Bison

I'm using Bison and Flex in an Xcode project. I didn't want to put the generated files under source control, so I was happy to find that Xcode natively supports Bison/Flex files, generating the parsers on-the-fly in its derived data folder. So far so good.
However, Xcode uses an embedded old Bison version (2.3):
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/yacc
which doesn't yet support the %define api.pure full directive. Since this bison executable is under the Xcode.app bundle I can't replace it, so I installed the latest version via Brew and added it to my $PATH through ~/.bash_profile (~/.bashrc also sources my bash profile). So in bash I can say:
$ which bison
/usr/local/Cellar/bison/3.0.4/bin//bison
However, Xcode still uses it's own version... I suppose the path to the internal bison is hardcoded.
My second approach was to create a custom build rule for Yacc files, and run the correct version of bison from there. This time the problem was that as Xcode ran my custom build rule, it immediately tried to build the resulting C files. The generated C files would however depend on the header file yet to be generated by Flex, because that's where e.g. yyscan_t is declared (used by Bison in the generated C file). But on the other hand, Flex-generated C files also include the Bison-generated header, so compiling with Flex first doesn't help...
What I need is to first only generate the Flex and Bison headers/sources and then build them along with the rest of the project.
How can I achieve this?
I've managed to solve the issue by putting the *.l and *.y files under a *.parser folder and adding that folder to the project. Then I removed the *.l and *.y files added the folder to the compiled sources:
And then made a Build Rule for *.parser like this:
This enables me to first run yacc and lex and only then will the resulting *.cpp files be passed to the compilation step.
If you go to your build target, Build Phases, and click the + on the bar with the search box on it, you can add a New Run Script Phase. You can then drag that above your current Compile Sources phase. You can do whatever you want in that script phase, and it will run before compilation starts.
This is a bit of a Zombie, but if I ever come back here again, I will want to see the answer.
Certainly from XCode 12 (probably before) the answer is trivially easy.
(1) Go to build settings
(2a) Press the + for a brand new setting variable.
(2b) Change the NAME to YACC, and it's VALUE to /usr/local/bin/bison (or whatever path you need for brew).
(3a) Press the + for a brand new setting variable.
(3b) Change the NAME to LEX, and it's VALUE to /usr/local/bin/flex (or whatever path you need for brew).
(4+) use the YACC/LEX settings for flags that you want to use.
I've managed to do it with custom build rules, using bison installed from brew and flex that comes with macOS, not the one bundled with Xcode. I'm not sure if my problem was the same as yours, but if you want to take a look my project is on GitHub.

USB GCC Development Environment with Libraries

I'm trying to get something of an environment on a usb stick to develop C++ code in. I plan to use other computers, most of the time linux, to work on this from a command line using g++ and make.
The problem is I need to use some libraries, like Lua and OpenGL, which the computers don't have. I cannot add them to the normal directories, I do not have root on these computers. Most of the solutions I've found involve putting things in /usr/lib/ and the like, but I cannot do that. I've also attempted adding options like '-L/media//lib', which is where they are kept, and it didn't work. When compiling, I get the same errors I got when first switching to an OS with the libraries not installed.
Is there somewhere on the computer outside of /usr/ I can put them, or a way to make gcc 'see' them?
You need more than the libraries to be able to compile code utilizing those libraries. (I'm assuming Linux here, things might be slightly different on e.g. OSX,BSDs,Cygwin,Mingw..)
Libraries
For development you need these 3 things when your code uses a library:
The library header files, .h files
The library development files, libXXX.so or libXXX.a typically
The library runtime files , libXXX.so.Y where Y is a version number. These are not needed if you statically link in the library.
You seem to be missing the header files (?) Add them to your usb stick, say under /media/include
Development
Use (e.g.) the compiler flag -I/media/include when compiling source code to refer to a non-standard location of header files.
Use the compiler/linker flag -L/media/lib to refer to non-standard location of libraries.
You might be missing the first step.
Running
For dynamically linked libraries, the system will load those only from default locations, typically /lib/ , /usr/lib/
Learn the ldd tool to help debug this step.
You need to tell the system where to load additional libraries when you're running a program, here's 3 alternatives:
Systemwide: Edit /etc/ld.so.conf and add /media/libs there. Run ldconfig -a afterwards.
Local, to the current shell only. set the LD_LIBRARY_PATH environment variable to refer to /media/lib, run export LD_LIBRARY_PATH=/media/lib
Executable: Hardcode the non-standard library path in the executable. You add this to the linking step when creating your executable: -Wl,-rpath,/media/lib
Etc.
There could be other reasons things are not working out, if so,
show us the output of ls -l /media/libs , and where you put the library header files, the command line you use to compile/link, and the exact errors you get.
Missing the headers and/or development libraries (for dynamic libraries there is usually a symlink from a libXXX.so to a libXXX.so.Y , the linker needs the libXXX.so , it will not look directly at libXXX.so.Y)
using libraries not compatible with your current OS/architecture. (libraries compiled on one linux distro is often not compatible with another distro, or even another minor version of the same distro)
using an usb stick with a FAT32 filesystem, you'll get in trouble with symlinks..

Scip integrate with mingw and msys

How can I integrate SCIP with MinGW and Msys?
Whilst you are waiting for a real answer, I can already guide you to this page from the official site on how to build SCIP (see below). For actual integration there is a pointer in the faq:
How do I construct a problem instance in SCIP?
First you have to create a SCIP object via SCIPcreate(), then you
start to build the problem via SCIPcreateProb(). Then you create
variables via SCIPcreateVar() and add them to the problem via
SCIPaddVar(). The same has to be done for the constraints. For
example, if you want to fill in the rows of a general MIP, you have to
call SCIPcreateConsLinear(), SCIPaddConsLinear() and additionally
SCIPreleaseCons() after finishing. If all variables and constraints
are present, you can initiate the solution process via SCIPsolve().
Make sure to also call SCIPreleaseVar() if you do not need the
variable pointer anymore. For an explanation of creating and releasing
objects, please see the doxygen documentation.
NOTE: See the directories "examples/MIPsolver/" and "examples/Queens/" for simple examples
Remarks on Building/Installing under Windows using MinGW (from http://scip.zib.de/doc/html/INSTALL.php)
To build your own Windows binaries under Windows, we recommend using
the MinGW-Compiler with MSYS from mingw.org
First install MSYS, then MinGW to the mingw folder inside the msys
folder. Now you need to install the following packages to the mingw
folder:
- zlib (or use ZLIB=false ZIMPL=false since zlib is needed for ZIMPL and ZIMPL-support in SCIP)
- pcre (or use ZIMPL=false since pcre is needed for ZIMPL and ZIMPL-support in SCIP)
- gmplib (or use ZIMPL=false since gmplib is needed for ZIMPL and ZIMPL-support in SCIP)
(After calling "make clean" in the ZIMPL folder you will also need
flex and bison to remake ZIMPL. We recommend NOT to use "make clean"
inside the ZIMPL-folder if you do not have these packages installed.)
You can download these additional packages as precompiled binaries for
example from: http://gnuwin32.sourceforge.net/packages.html
(zlib&pcre) http://cs.nyu.edu/exact/core/gmp/ (gmplib) or compile the
source on your own from the project homepages: http://www.zlib.net/
http://www.pcre.org/ http://www.gmplib.org/ (The command "./configure
--prefix=/mingw ; make ; make install" should succeed without problems and installs the packages into the mingw folder.)
Now "make READLINE=false" should be compiling without errors. Please
note that we do NOT support creating the doxygen documentation or
readline-usage under Windows.
Since there are no real symlinks in MSYS, the include and library
files of SoPlex and ZIMPL are actually copied into the
SCIP-lib-folder. When you recompile ZIMPL or SoPlex after compiling
SCIP you have to copy the libraries manually into the SCIP-lib-folder
and recompile SCIP afterwards.

New Qt Directory is not valid

I've written an application using Qt on OS X. The installed SDK automatically installed as a framework which I didn't want. So I cloned their newest version from the Qt git repository and built it from source as static libraries. I would like it to compile using those static libraries instead of the framework but in preferences in setting the version/Path of Qt no matter what path I direct it to it says it's not a valid Qt directory. What has to be in a qt Directory that constitutes it being valid?
I'm closing this, The problem was installing on OSX I needed to declare -no-framework when running configure.
Some tips;
Install into a path that doesn't contain spaces
Use -prefix $PWD from the current path, and set the PATH, INCLUDE and LIB env variables appropriately - this makes it possible to have multiple Qt builds, e.g. multiple shadow builds from one source directory
Don't do static configure - it makes using plugins difficult, and assuming you use LGPL you have to ship the .o files.

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