Functions to find libaries and include directories

The qibuild CMake framework contains several -config.cmake files when upstream Find-.cmake files are not correct or missing.

For instance, the canonical FindFoo.cmake looks like:

include(FindPackageHandleStandardArgs.cmake)

find_path(FOO_INCLUDE_DIR foo/foo.h)
find_library(FOO_LIBRARY foo)

find_package_handle_standard_args(FOO
 DEFAULT_MSG
  FOO_INCLUDE_DIR
  FOO_LIBRARY
)

mark_as_advanced(FOO_LIBRARY FOO_INCLUDE_DIR)

if(FOO_FOUND)
  set(FOO_LIBRARIES    ${FOO_LIBRARY})
  set(FOO_INCLUDE_DIRS ${FOO_INCLUDE_DIR})
endif()

There is a lot of boilerplate code here, and it’s not easy to know the names of the variables (is it FOO_INCLUDE_DIR or FOO_INCLUDE_DIRS ?)

For qibuild, we use the concept of PREFIX and exported variables will always be ${${PREFIX}_INCLUDE_DIRS} and ${${PREFIX}_LIBRARIES}

Thus, foo-config.cmake can simply be rewritten as:

clean(FOO)
fpath(FOO foo/foo.h)
flib(FOO  foo)
export(FOO)

Note that the exported variables will always be all upper-case, will contain no version number and will have the plural form.

  • FOO_INCLUDE_DIRS
  • FOO_LIBRARIES

Also note that FOO_LIBRARIES will equal either:

"general;/path/to/foo.so"

if flib() was called with no specific argument or:

"debug;/path/to/foo_d.lib;optimized;/path/to/foo.lib"

if both flib(FOO OPTIMIZED ...) and flib(FOO DEBUG ...) have been called.

So this variable can be used directly in the target_link_libraries() call

clean

clean(prefix)
Arguments:
  • prefix – The prefix of the variables to clean

Cleanup variables related to a library/executable/source-only library Use this at the start of the ${prefix}-config.cmake file

fpath

fpath(prefix path [<remaining args> ...]
)
Arguments:
  • prefix – The prefix of the exported variables. Must match the argument of clean() and export_lib() (or export_header for a header-only library) calls.
  • path – The path of one of the headers inside the include directory.
  • args (remaining) – The remaining arguments will be passed to find_path

Search for an include directory

A small example, assuming /usr/local/include/foo/foo.h exists.

If you use:

fpath(FOO foo/foo.h)

FOO_INCLUDE_DIRS will equal /usr/local/include, so you will have to use

#include <foo/foo.h>

Whereas if you use

fpath(FOO foo.h PATH_SUFFIXES foo)

FOO_INCLUDE_DIRS will equal usr/local/include/foo, so you will have to use

#include <foo.h>

flib

flib(prefix name [DEBUG]
    [OPTIMIZED]
    [<remaining args> ...]
)
Arguments:
  • prefix – The prefix of the exported variables. Must match the argument of clean() and export() calls.
  • name – The name of the library
  • DEBUG – find a library that will be used for a debug build
  • OPTIMIZED – find a library that will be used for an optimized build
  • args (remaining) – The remaining arguments will be passed to find_library

Search for a library

Note: if the library has a different name in debug and in release, you should use:

flib(foo DEBUG     foo_d)
flib(foo OPTIMIZED foo)

fprogram

fprogram(prefix)
Arguments:
  • prefix – Prefix of the variables to export. Must match the calls to clean() and export_bin() calls.

Search for an executable

export_lib

export_lib(prefix)
Arguments:
  • prefix – The prefix of the exported variables

Export the variables related to a library

Use this at the end of the ${prefix}-config.cmake find_package_handle_standard_args will be called to make sure ${prefix}_LIBRARIES and ${prefix}_INCLUDE_DIRS have been found.

export_lib_pkgconfig

export_lib_pkgconfig()

Helper function to use with pkgconfig.

Usage, assuming foo-1.0.pc is somewhere in PKG_CONFIG_PATH

clean(FOO)
find_package(PkgConfig)
pkg_check_modules(FOO foo-1.0)
export_lib_pkgconfig(FOO)

export_bin

export_bin(prefix)
Arguments:
  • prefix – The prefix of the variables to export

Export the variables related to an executable

Use at the end of foo-config.cmake

fprogram(FOO RELEASE foo)
fprogram(FOO OPTIMIZED foo_d)
export_bin(FOO)

Here, FOO_EXECUTABLE will be set to ‘/path/to/foo.exe’, and FOO_EXECUTABLE_DEBUG to ‘path/to/foo_d.exe’

export_header

export_header(prefix)
Arguments:
  • prefix – The prefix of the variables to export

Export the variables related to an header-only library

Use at the end of foo-config.cmake

clean(FOO)
fpath(FOO foo/foo.h)
export_header(FOO)
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