Using qi_install functions

qi_install functions are simply wrappers for install upstream CMake functions.

Here are a few concepts you need to understand to properly use qi_install functions

Components

The various qi_install_* function deals with the components and respect the SDK layout for you.

There are 3 sort of dependencies in qibuild, which match 3 install components:

  • build: the dependencies required to build the software. (headers, statics libraries, CMake files). You will need that if you want to generate a package containing a pre-compiled library for other people to link with, for instance.
  • runtime: the dependencies required to run the software. (executable, dynamic libraries, data, config files)
  • test : the dependencies required to test the software (the gtest library, some test executables, ...)

Install functions, destination, components

Note that the qi_create_* and the qi_stage_lib functions create correct install rules for you by default.

function component destination
qi_create_bin runtime bin/
qi_create_lib(SHARED) runtime lib/ on UNIX, bin/ on windows
qi_install_conf runtime etc/
qi_install_data runtime share/
qi_create_lib(STATIC) build lib/
qi_stage_lib(foo) build share/cmake/modules/foo/foo-config.cmake
qi_install_header build include/
qi_create_test_helper test bin/

Other use cases

If you don’t want the executable to be installed (because it’s just used at build time, for instance), you can use:

qi_create_bin(foo NO_INSTALL)

If you want to install an executable that is NOT the result of a compilation (for instance a script), you can use qi_install_program

If you want to install something in your development install that does not fit in these destinations (say, an example), you can use the generic qi_install function with DESTINATION and COMPONENT arguments.

Special features

qi_install ends up calling regular install() CMake functions, but there are some differences, here are a few

Check of arguments

If you try to install a file that does not exist, using install() will exit during installation, but qi_install will exit during configuration. This does no prevent you from installing generated files, but you have to make sure the are generated before creating the install rule.

# Always generate files in cmake build dir:
set(_out ${CMAKE_CURRENT_BINARY_DIR}/foobar)
configure_file(foobar.in "${_out}")
qi_install("${_out}"
  DESTINATION /etc/init.d/
  )

# Note the trailing "/" at the end of the DESTINATION argument.

# Do NOT use:
qi_install("${_out}"
  DESTINATION /etc/init.d/foobar
  )

# or you'll end up with /etc/init.d/foobar/foobar ...

Support of glob and directories

Please not that on top of this, you can use directories, globbing expressions and list of files as arguments on all qi_install_* functions.

For instance

qi_install(foo/bar/ *.txt spam.cfg eggs.cfg DESTINATION "prefix")

will install:

  • directory foo/bar to “prefix/bar”
  • every .txt file in current directory to “prefix”
  • the spam and eggs cfg file to “prefix”

Note the glob is not recursive by default.

If you really need it, just use:

qi_install(foo/*.hpp RECURSE)

“IF” keyword

Instead of using

if(FOO)
  qi_install(.... )
endif()

you can use

qi_install(.... IF FOO)

SUBFOLDER and KEEP_RELATIVE_PATHS keywords

qi_install functions accept either a SUBFOLDER or a KEEP_RELATIVE_PATHS keyword.

It is easier to understand the meaning of these keywords by an example.

Using SUBFOLDER

You should use this for instance with headers in several different folders (a bit like an autotools project):

sources:                      destination
  foo                          include
  |__ include                  |__ foo
      |__ foo.h                       |__ foo.h
      |__ bar.h                       |__ bar.h
  config.h (generated)                |__ config.h
qi_install_header(foo
                 HEADERS
                   foo/include/foo.h
                   foo/include/bar.h
                   ${CMAKE_BUILD_DIR}/config.h
                 SUBFOLDER foo)

qi_install_header will set DESTINATION “include” for you, but you need ‘SUBFOLDER foo’ argument to tell CMake to install files to include/foo, regardless their original path.

Using KEEP_RELATIVE_PATHS

You should you this for instance with headers following the exact same hierarchy in the source tree and when installed (a bit like boost):

sources                         destination
  libfoo                        include
  |__ foo                       |__ foo
      |__ foo.h                     |__ foo.h
      bar                           bar
      |__ bar.h                     |__ bar.h
          baz                           baz
          |__ baz.h                     |__ baz.h
qi_install_header(foo
                  HEADERS
                    foo/foo.h
                    bar/bar.h
                    bar/baz/baz.h
                  KEEP_RELATIVE_PATHS)

qi_install_header will set DESTINATION “include” for you, and you do not need SUBFOLDER because KEEP_RELATIVE_PATHS is set.

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