cupcake.cmake is a CMake module. It is named with the .cmake extension to distinguish it from cupcake.py, which is a Python tool for working with Conan and CMake projects, with additional features for projects using cupcake.cmake.
cupcake.cmake requires CMake >= 3.21.
The recommended method to import cupcake.cmake is with
find_package()
:
find_package(cupcake.cmake REQUIRED)
Unlike include()
, find_package()
lets us easily
check version compatibility and lean on package managers like Conan.
For that to work, an installation must be found on the
CMAKE_PREFIX_PATH
.
There are a few ways to accomplish that.
First, add cupcake.cmake
as a non-tool1 requirement to your Conan recipe:
requires = ['cupcake.cmake/1.2.2']
Second, tell Conan how to find cupcake.cmake. You can either:
-
Point it to my public Redirectory:
conan remote add redirectory https://conan.jfreeman.dev
-
Copy the recipe from this project:
conan export .
# In this project:
cmake -B <build-dir> -DCMAKE_INSTALL_PREFIX=<path> .
cmake --build <build-dir> --target install
# In your project:
cmake -B <build-dir> -DCMAKE_PREFIX_PATH=<path> .
Alternatively, you can embed this project in yours as a submodule and import
it with add_subdirectory()
:
add_subdirectory(path/to/cupcake.cmake)
There are two categories of commands, general and special.
General commands have no special requirements,
but special commands require a cupcake.json
file
in the project's root directory.
Special commands effectively relocate essential CMake configuration data
from multiple CMake listfiles sprinkled throughout a project
to a single JSON file that is more easily read and written by other tools.
Special commands are documented with example cupcake.json
and Pythonic pseudocode.
cupcake_project
cupcake_find_package
cupcake_add_subproject
cupcake_add_library
cupcake_add_executable
cupcake_enable_testing
cupcake_add_test
cupcake_install_project
cupcake_install_cpp_info
cupcake_find_packages
cupcake_link_libraries
cupcake_add_libraries
cupcake_add_executables
cupcake_add_tests
A project using only general commands might look like this:
# CMakeLists.txt
cmake_minimum_required(VERSION 3.21)
project(example LANGUAGES CXX)
find_package(cupcake REQUIRED)
cupcake_project()
cupcake_find_package(abc)
cupcake_add_library(example)
target_link_libraries(${this} PUBLIC abc::abc)
cupcake_add_executable(example)
target_link_libraries(${this} PUBLIC example.libexample)
cupcake_enable_testing()
cupcake_install_project()
cupcake_install_cpp_info()
# tests/CMakeLists.txt
cupcake_find_package(xyz PRIVATE)
cupcake_add_test(example)
target_link_libraries(${this} PUBLIC xyz::xyz example.libexample)
A project using special commands might look like this:
# CMakeLists.txt
cmake_minimum_required(VERSION 3.21)
project(example LANGUAGES CXX)
find_package(cupcake REQUIRED)
cupcake_project()
cupcake_find_packages(main)
cupcake_link_libraries(example.imports.main INTERFACE main)
cupcake_add_libraries()
cupcake_add_executables()
cupcake_enable_testing()
cupcake_install_project()
cupcake_install_cpp_info()
# tests/CMakeLists.txt
cupcake_find_packages(test PRIVATE)
cupcake_link_libraries(example.imports.test INTERFACE test)
cupcake_add_tests()
// cupcake.json
{
"project": {
"name": "example"
},
"imports": [
{ "name": "abc", "file": "abc", "targets": ["abc::abc"] },
{ "name": "xyz", "file": "xyz", "targets": ["xyz::xyz"], "groups": ["test"] }
],
"libraries": [
{ "name": "example", "links": ["abc::abc"] }
],
"executables": [
{ "name": "example", "links": [{ "target": "example.libexample", "scope": "PUBLIC" }] }
],
"tests": [
{
"name": "example", "links": [
"xyz::xyz",
{ "target": "example.libexample", "scope": "PUBLIC" }
]
}
]
}
cupcake_project()
Define project variables used by other cupcake.cmake commands, and choose different defaults for built-in CMake commands and variables.
cupcake_project()
must be called after a call of the built-in CMake command
project()
and before any other cupcake.cmake commands in that project.
It should be called in the project's root CMakeLists.txt
.
The recommended pattern looks like this:
project(${PROJECT_NAME} LANGUAGES CXX)
find_package(cupcake REQUIRED)
cupcake_project()
cupcake_project()
takes no arguments directly,
instead taking them all from the variables set by the call to project()
.
I would have liked this command to wrap the call to project()
, if possible,
but CMake requires a "literal, direct call to the project()
command" in
the root CMakeLists.txt
, and thus it cannot be wrapped.
cupcake_project()
adds one special INTERFACE
library target,
${PROJECT_NAME}.imports.main
,
that projects can use to aggregate the "main" group of required libraries.
Other targets can conveniently link to this one target
instead of to each requirement individually,
and automatically link to new requirements as they are added.
Projects can use the special command cupcake_link_libraries()
to link all the "main" required libraries listed in cupcake.json
.
cupcake_project()
adds three more special internal targets:
-
${PROJECT_NAME}.libraries
: AnINTERFACE
library target. -
${PROJECT_NAME}.executables
: A custom target. -
${PROJECT_NAME}.tests
: A custom target.
All three are excluded from the "all" target.
Each has an external alias with the same name,
except the dot (.
) is replaced with a double colon (::
).
They each depend on all of the libraries,
executables, or tests,
respectively, added (by a cupcake_add_<target>()
command)
in the project directly , i.e. not in a subproject.
Further, if the project is the root project,
equivalent targets are available under the unqualified names
libraries
, executables
, and tests
, respectively.
These targets are intended to be automatic groups
with names that can be easily passed to cmake --build
.
cupcake_project()
changes these default behaviors:
# | Variable | Value |
---|---|---|
1 | CMAKE_POLICY_DEFAULT_CMP0087 |
NEW |
2 | CMAKE_FIND_PACKAGE_PREFER_CONFIG |
TRUE |
3 | CMAKE_FIND_PACKAGE_SORT_ORDER |
NATURAL |
3 | CMAKE_FIND_PACKAGE_SORT_DIRECTION |
DEC |
4 | CMAKE_MODULE_PATH |
${CMAKE_CURRENT_SOURCE_DIR}/external |
5 | CMAKE_CXX_VISIBILITY_PRESET |
hidden |
5 | CMAKE_VISIBILITY_INLINES_HIDDEN |
TRUE |
6 | CMAKE_EXPORT_COMPILE_COMMANDS |
TRUE |
7 | CMAKE_BUILD_RPATH_USE_ORIGIN |
TRUE |
7 | CMAKE_INSTALL_RPATH |
${origin} ${origin}/${relDir} |
8 | CMAKE_RUNTIME_OUTPUT_DIRECTORY |
${CMAKE_OUTPUT_PREFIX}/${CMAKE_INSTALL_BINDIR} |
8 | CMAKE_LIBRARY_OUTPUT_DIRECTORY |
${CMAKE_OUTPUT_PREFIX}/${CMAKE_INSTALL_LIBDIR} |
8 | CMAKE_ARCHIVE_OUTPUT_DIRECTORY |
${CMAKE_OUTPUT_PREFIX}/${CMAKE_INSTALL_LIBDIR} |
- Lets
install(CODE)
use generator expressions, which is required bycupcake_install_cpp_info()
. - Makes
find_package()
try Config mode before Module mode by default. - Sorts packages by latest semantic version when multiple versions are installed.
- Lets
find_package()
find the project's Find Modules. - Treats symbols in shared libraries as private by default, hiding them.
Harmonizes the default on non-Windows platforms
with the existing defaults on Windows and for C++ modules.
Public symbols must be explicitly exported with annotations.
These annotations are supplied by preprocessor macros
defined in headers generated for each library by
cupcake_add_library()
.2 - Generates a "compilation database" file (
compile_commands.json
) used by language servers like clangd. - Uses relative rpaths both when building and installing, which lets you move your build directory or install prefix without breaking the executables underneath.
- See section "Output directory".
cupcake_project()
adds these project variables (different for each subproject):
-
PROJECT_EXPORT_SET
: The name of the default export set for the project's exported targets. -
PROJECT_EXPORT_DIR
: The directory in which to place generated export files, i.e. the package configuration file, the package version file, and any target export files. -
${PROJECT_NAME}_FOUND
:TRUE
, to short-circuit calls tofind_package()
looking for this project's package from other subprojects, e.g. examples or siblings.
cupcake_project()
adds these global variables (same for all subprojects):
-
CMAKE_PROJECT_EXPORT_SET
: ThePROJECT_EXPORT_SET
of the root project. -
CMAKE_INSTALL_EXPORTDIR
: The path, relative to the installation prefix (CMAKE_INSTALL_PREFIX
), in the style ofGNUInstallDirs
, at which to install CMake package configuration files and other project metadata files (e.g.cpp_info.py
installed bycupcake_install_cpp_info()
). In other words, the stringshare
. -
CMAKE_OUTPUT_DIR
: See section "Output directory". -
CMAKE_OUTPUT_PREFIX
: See section "Output directory". -
CMAKE_HEADER_OUTPUT_DIRECTORY
: See section "Output directory".
CMake has a variable, CMAKE_RUNTIME_OUTPUT_DIRECTORY
,
that chooses the default value for the target property
RUNTIME_OUTPUT_DIRECTORY
,
which chooses the output directory for RUNTIME
targets,
which includes executables on all platforms and DLLs on Windows.
That is, each runtime target (an executable or a DLL)
has a property RUNTIME_OUTPUT_DIRECTORY
that chooses where it is placed,
and the default value for that target property is the value of the variable
CMAKE_RUNTIME_OUTPUT_DIRECTORY
when the target is added
(with add_executable()
or add_library()
).
Setting this variable is necessary on Windows to ensure that DLLs end up in
the same directory as the executables (including tests) that load them,
which is where those executables look for them.
We can use this variable and its cousins,
CMAKE_ARCHIVE_OUTPUT_DIRECTORY
(for static libraries) and
CMAKE_LIBRARY_OUTPUT_DIRECTORY
(for shared libraries on non-Windows platforms),
to construct at build-time (i.e. before installation) a directory
structure that mimics, in part, the structure that will be created by an
installation, and isolated from the intermediate files littering the build
directory.
In other words, they let us create a pseudo-installation
where builders (and tools) can inspect and use
the interesting outputs of a build before they are installed,
including outputs like tests that will not be installed.
Each build configuration requires a separate pseudo-installation
because they are not guaranteed to use unique file names.
Each pseudo-installation is rooted at a CMAKE_OUTPUT_PREFIX
,
akin to CMAKE_INSTALL_PREFIX
.
All output prefixes are nested under a common output directory,
CMAKE_OUTPUT_DIR
, akin to CMAKE_BINARY_DIR
.
In fact, CMAKE_OUTPUT_PREFIX
is just ${CMAKE_OUTPUT_DIR}/$<CONFIG>
.
There is no similar variable
choosing the output directory for generated headers,
just like there is no add_header()
command
to add a generated header as a target.
cupcake.cmake fills this gap by defining the variable
CMAKE_HEADER_OUTPUT_DIRECTORY
.
Generated headers are not configuration-specific, though,
so they are not placed under any output prefix.
Instead, CMAKE_HEADER_OUTPUT_DIRECTORY
is just
${CMAKE_OUTPUT_DIR}/Common/${CMAKE_INSTALL_INCLUDEDIR}
.
cupcake_find_package(<package-name> [<version>] [PRIVATE] ...)
Import targets from a requirement by calling find_package()
.
<version>
is forwarded to find_package()
,
but it is an optional parameter for this command.
I recommend that you do not include it.
Instead, version declaration and checking should happen
at the package manager level, e.g. in your Conan recipe.
In the underlying call to find_package()
,
REQUIRED
is always passed so that missing requirements raise an error.
Optional requirements should always be guarded by an option,
e.g. with_xyz
, rather than
conditionally linking based on whether or not CMake succeeded in finding them.
Unless PRIVATE
is passed, this command saves the package name
(but not the version, even when given)
in a list of dependencies for the project.
That list is kept in a DIRECTORY
property
of PROJECT_SOURCE_DIR
named PROJECT_DEPENDENCIES
.
It affects the behavior of
cupcake_install_project()
:
the generated package configuration file will transitively call
find_dependency()
for all non-private dependencies.
Remaining arguments are passed through to find_package()
.
cupcake_find_package()
returns a variable <package-name>_TARGETS
containing a list of the targets imported by the command.
cupcake_add_subproject(<name> [PRIVATE] [<path>])
Import targets from a requirement by calling
add_subdirectory()
.
<path>
is forwarded to add_subdirectory()
as the <source_dir>
argument.
If it is absent, then <name>
is used instead.
Relative paths, like the subproject name,
are relative to CMAKE_CURRENT_SOURCE_DIR
.
<name>
should match the name passed to the project()
command in
the CMakeLists.txt
of the subdirectory.
PRIVATE
has the same meaning as it does for
cupcake_find_package()
.
cupcake_add_library(<name> [PRIVATE])
Add targets for a library by calling add_library()
.
Unless PRIVATE
is passed, the library is exported,
meaning it is included when installing the project.
PRIVATE
libraries can be good for sharing code among tests.
cupcake_add_library()
adds an internal target named ${PROJECT_NAME}.libraries.<name>
,
with an abbreviated alias named ${PROJECT_NAME}.l.<name>
.
If the library has the same name as the project,
then it is the project's default library target
and gets the additional alias ${PROJECT_NAME}.library
.
If the library is exported,
then cupcake_add_library()
adds external ALIAS
targets
matching all of the above names,
but with the dot (.
) separators replaced with double colons (::
),
i.e. ${PROJECT_NAME}::libraries::<name>
, ${PROJECT_NAME}::l::<name>
,
and ${PROJECT_NAME}::library
.
Commands in the same project should use the internal target name.
Commands in different projects,
even if they are children (e.g. examples) or siblings
(e.g. fellow dependencies) sharing the same root project,
should use the external target name.
The external target names match the ones supplied by
the installed package configuration file
(see cupcake_install_project()
)
and/or the installed cpp_info.py
script
(see cupcake_install_cpp_info()
).
The internal target is added as a dependency
of the internal INTERFACE
library target ${PROJECT_NAME}.libraries
,
which has an external alias ${PROJECT_NAME}::libraries
,
and an internal alias libraries
if the project is the root project
(see cupcake_project()
).
cupcake_add_library()
returns a variable, this
,
with the name of the internal target
for convenient use in subsequent commands.
Commands configuring the target should be called immediately after it,
to keep all of a target's configuration in one place.
A library's public headers must be either
the single file include/<name>.hpp
(or .h
)
or every file under the directory include/<name>/
.
Private headers may be placed under src/lib<name>/
.
Exported libraries export their public headers only.
If a library has sources, they should be either
the single file src/lib<name>.cpp
or every .cpp
file under the directory src/lib<name>/
.
If a library does not have sources, i.e. if it is a header-only library,
then the target will be an INTERFACE
library.
If a library does have sources, then the target will be a
STATIC
or SHARED
library depending on the value of variable
BUILD_SHARED_LIBS
.
A library may include
its own public headers by their paths relative to include/
,
and its own private headers by their paths relative to the project's
root directory (i.e. starting with src/lib<name>/
),
but it may not include other headers in the project,
even relative to those same directories,
unless it links to a library exporting those headers.
In fact, it cannot include unlinked headers
because cupcake_add_library()
creates temporary symbolic links
in the build directory pointing to the permitted headers,
and only those will be found by the compiler.
Each library is given two generated headers. These headers are installed with the library (if it is installed). Libraries must not define their own public headers with these names.
-
<name>/export.hpp
: An export header with preprocessor macros for annotating public and deprecated symbols in shared libraries.${NAME_UPPER}_EXPORT
${NAME_UPPER}_DEPRECATED
-
<name>/version.hpp
: A version header with preprocessor macros deconstructing the package version string.-
${NAME_UPPER}_VERSION
: A string literal ofPROJECT_VERSION
. -
${NAME_UPPER}_VERSION_MAJOR
: An integer expression equal toPROJECT_VERSION_MAJOR
. -
${NAME_UPPER}_VERSION_MINOR
: An integer expression equal toPROJECT_VERSION_MINOR
. -
${NAME_UPPER}_VERSION_PATCH
: An integer expression equal toPROJECT_VERSION_PATCH
.
-
cupcake_add_executable(<name> [PRIVATE])
Add targets for an executable by calling
add_executable()
.
Unless PRIVATE
is passed, the executable is exported,
meaning it is included when installing the project.
PRIVATE
executables can be good for manual testing.
cupcake_add_executable()
adds an internal target named ${PROJECT_NAME}.executables.<name>
,
with an abbreviated alias named ${PROJECT_NAME}.e.<name>
.
If the executable has the same name as the project,
then it is the project's default executable target
and gets the additional alias ${PROJECT_NAME}.executable
.
If the executable is exported,
then cupcake_add_executable()
adds external ALIAS
targets
matching all of the above names,
but with the dot (.
) separators replaced with double colons (::
),
i.e. ${PROJECT_NAME}::executables::<name>
, ${PROJECT_NAME}::e::<name>
,
and ${PROJECT_NAME}::executable
.
Commands in the same project should use the internal target name.
Commands in different projects,
even if they are children (e.g. examples) or siblings
(e.g. fellow dependencies) sharing the same root project,
should use the external target name.
The external target names match the ones supplied by
the installed package configuration file
(see cupcake_install_project()
)
and/or the installed cpp_info.py
script
(see cupcake_install_cpp_info()
).
The internal target is added as a dependency
of the internal custom target ${PROJECT_NAME}.executables
,
which has no external alias,
but has an internal alias executables
if the project is the root project
(see cupcake_project()
).
cupcake_add_executable()
returns a variable, this
,
with the name of the internal target
for convenient use in subsequent commands.
Commands configuring the target should be called immediately after it,
to keep all of a target's configuration in one place.
An executable must have sources, and they should be either
the single file src/<name>.cpp
or every .cpp
file under the directory src/<name>/
.
An executable may include
its own private headers by their paths relative to the project's
root directory (i.e. starting with src/<name>/
),
but it may not include other headers in the project,
even relative to the same directory,
unless it links to a library exporting those headers.
In fact, it cannot include unlinked headers
because cupcake_add_library()
creates temporary symbolic links
in the build directory pointing to the permitted headers,
and only those will be found by the compiler.
cupcake_add_executable()
adds two more internal targets.
The first is named execute.${PROJECT_NAME}.<name>
,
aliased as execute.<name>
if the project is the root project,
and as execute
if the executable name matches the project name too.
It is a custom target that executes the executable.
You can invoke it yourself with the following command
instead of digging around in the output directory to find the executable.
cmake --build <build-dir> --target execute.<name>
Additionally, the target passes any
CMake list of command-line arguments
found in the environment variable CUPCAKE_EXE_ARGUMENTS
.3
In other words,
if you want to pass any command-line arguments
through the custom target to the executable,
then you must set environment variable CUPCAKE_EXE_ARGUMENTS
to a semicolon-separated (;
) list of string arguments,
where each argument internally escapes any semicolons (with \;
)
and is double-quoted ("
) if it contains any whitespace.
If you use cupcake.py, then it will set CUPCAKE_EXE_ARGUMENTS
to forward any trailing arguments you pass to cupcake exe <name>
.
The second target is named debug.${PROJECT_NAME}.<name>
,
aliased as debug.<name>
if the project is the root project,
and as debug
if the executable name matches the project name too.
It is a custom target that works almost like execute.${PROJECT_NAME}.<name>
,
except that it executes GDB, the GNU debugger, on the executable target,
and initializes it with a command file
that sets the command line arguments found in CUPCAKE_EXE_ARGUMENTS
and then copies whatever is in the .gdbinit
file of your current directory.
If you use cupcake.py, then it will set CUPCAKE_EXE_ARGUMENTS
to forward any trailing arguments you pass to cupcake debug <name>
.
cupcake_enable_testing()
Conditionally add tests to the project,
in the style of enable_testing()
.
The command does nothing if the project is not top-level. Dependents generally want to run a dependency's tests only when the dependency is installed, if at all, not every time the dependent runs its own tests.
If the project is top-level, then the command imports the CTest module.
If BUILD_TESTING
is ON
, which it is by default,
then the command calls add_subdirectory(tests)
and adds a special INTERFACE
library target
named ${PROJECT_NAME}.imports.test
,
akin to the ${PROJECT_NAME}.imports.main
target
added by cupcake_project()
,
i.e. a convenient target that projects can use
to aggregate the "test" group of required libraries.
Individual tests should be added in the CMakeLists.txt
of the tests/
subdirectory.
Dependencies that only the tests require should be imported there too.
cupcake_add_test(<name>)
Add targets for an executable by calling
add_executable()
,
and add a CMake test whose command executes that executable by calling
add_test()
.
In CMake's documentation, the term "test", which I call here a "CMake test",
refers to a command that exits with code 0 if and only if it passes.
Typical commands simply execute an executable target in the project.
cupcake_add_test()
implements exactly this pattern.
In this document, the term "test" refers to
the executable, the target, and the CMake test as a single unit.
Where necessary, I differentiate them.
cupcake_add_test()
adds an internal target named ${PROJECT_NAME}.tests.<name>
,
with an abbreviated alias named ${PROJECT_NAME}.t.<name>
,
as a dependency of the target ${PROJECT_NAME}.tests
.
If the project is the root project,
then it gives the internal target additional unqualified aliases
tests.<name>
and t.<name>
and adds it as a dependency of the unqualified target tests
.
Tests are never exported, meaning they are never installed
nor given external targets.
cupcake_add_test()
defines the variable this
in the parent scope
just like cupcake_add_library()
and for the same reason.
The target is excluded from the "all" target. This way, resources are not spent building tests unless they are run.
cupcake_add_test()
should be called only from the tests
subdirectory,
where all tests should live.
The executable must have sources,
and they should be either the single file tests/<name>.cpp
or every .cpp
file under the directory tests/<name>/
.
The executable may include
its own private headers by their paths relative to the project's
root directory (i.e. starting with tests/<name>/
),
but it may not include other headers in the project,
even relative to the same directory,
unless it links to a library exporting those headers.
In fact, it cannot include unlinked headers
because cupcake_add_library()
creates temporary symbolic links
in the build directory pointing to the permitted headers,
and only those will be found by the compiler.
The CMake test is added to the list of tests run by CTest. It is given a fixture that builds (or rebuilds) the executable before it is run.
cupcake_install_project()
Add rules to install all exported targets.
cupcake_install_project()
installs a package configuration file that
calls find_dependency()
for all non-PRIVATE
packages imported with
cupcake_find_package()
, and
exports all non-PRIVATE
libraries and
executables added
(by cupcake_add_<target>()
commands) in the project directly,
i.e. not in a subproject.
These targets are exported with their external names,
i.e. qualified by the project namespace,
e.g. ${PROJECT_NAME}::libraries::<name>
.
cupcake_install_project()
installs a package version file too.
cupcake_install_project()
should be called only once,
after all exported targets have been added.
It should be called from the project's root CMakeLists.txt
.
cupcake_install_cpp_info()
Add rules to install package metadata for Conan.
This command adds an installation rule to install a Python script at
${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_EXPORTDIR}/<PackageName>/cpp_info.py
.
That script can be executed within the package_info()
method
of a Python Conan recipe (conanfile.py
) to fill in the details of the
cpp_info
attribute:
def package_info(self):
path = f'{self.package_folder}/share/{self.name}/cpp_info.py'
with open(path, 'r') as file:
exec(file.read(), {}, {'self': self.cpp_info})
cupcake_find_packages(<group> ...)
Import targets from all requirements belonging to a group.
cupcake_find_packages()
first selects all objects in the .imports
array
of cupcake.json
with a .groups
array property (default value ["main"]
)
that contains <group>
.
Then, it calls cupcake_find_package()
for each selected object, passing the .file
string property of the object
(or if that is missing, the .name
string property)
and any additional arguments that were passed to cupcake_find_packages()
.
{
"imports": [
{ "name": "a", "file": "a", "targets": ["a::a"] },
{ "name": "b", "file": "b", "targets": ["b::b"], "groups": ["main"] },
{ "name": "c", "file": "c", "targets": ["c::c"], "groups": ["test"] }
]
}
def cupcake_find_packages(group, *args):
metadata = json.parse('cupcake.json')
for package in metadata.get('imports', []):
if group in package.get('groups', ['main']):
cupcake_find_package(package['file'] or package['name'], *args)
Note: The .name
property is the name of the package in the Conan ecosystem,
while the .file
property is the name of the package configuration file
that the CMakeDeps
generator generates for it,
corresponding to the cmake_file_name
property
of the package recipe's cpp_info
.
When the cmake_file_name
property is missing,
CMakeDeps
uses the package name as its default value.
cupcake_link_libraries(<target> <scope> <group>)
Link a target to all imported targets of all requirements belonging to a group.
cupcake_link_libraries()
is typically called
to link a convenience INTERFACE
target,
e.g. ${PROJECT_NAME}.imports.main
or ${PROJECT_NAME}.imports.test
,
to the targets of its corresponding requirement group, following a call
to cupcake_find_packages()
for that group.
cupcake_link_libraries()
first selects all objects in the .imports
array
of cupcake.json
with a .groups
array property (default value ["main"]
)
that contains <group>
.
Then, it calls target_link_libraries()
for each selected object, passing <target>
, <scope>
, and
the .targets
array property of the object.
<scope>
must be a scope keyword,
one of PUBLIC
, PRIVATE
, or INTERFACE
.
When <target>
is an INTERFACE
target, <scope>
must be INTERFACE
.
{
"imports": [
{ "name": "a", "file": "a", "targets": ["a::a"] },
{ "name": "b", "file": "b", "targets": ["b::b"], "groups": ["main"] },
{ "name": "c", "file": "c", "targets": ["c::c"], "groups": ["test"] }
]
}
def cupcake_link_libraries(target, scope, group):
metadata = json.parse('cupcake.json')
for package in metadata.get('imports', []):
if group in package.get('groups', ['main']):
name = package['name']
targets = package.get('targets', [f'{name}::{name}'])
target_link_libraries(target, scope, targets)
cupcake_add_libraries()
Add targets for all libraries in the project.
For each object in the .libraries
array of cupcake.json
,
cupcake_add_libraries()
first calls
cupcake_add_library()
with the object's .name
string property,
passing PRIVATE
if the object has a .private
Boolean property
that is true
.
Then it calls target_link_libraries()
for each value in the object's .links
array property.
Each link takes one of two forms.
If it is a string, then cupcake_add_libraries()
calls
target_link_libraries()
with it as the name of the linked target
and PUBLIC
as the scope.
If it is an object, then cupcake_add_libraries()
calls
target_link_libraries()
with its .target
string property
as the name of the linked target and
its optional .scope
string property (default value PUBLIC
) as the scope.
{
"libraries": [
{ "name": "x", "links": ["a::a"] },
{ "name": "y", "links": ["b::b", { "target": "c::c", "scope": "PRIVATE" }
]
}
def cupcake_add_libraries():
metadata = json.parse('cupcake.json')
for library in metadata.get('libraries', []):
target = cupcake_add_library(
library['name'], PRIVATE if library['private'] else None
)
for link in library.get('links', []):
if type(link) == str:
target_link_libraries(target, PUBLIC, link)
else:
target_link_libraries(target, link.get('scope', PUBLIC), link['target'])
cupcake_add_executables()
Add targets for all executables in the project.
For each object in the .executables
array of cupcake.json
,
cupcake_add_executables()
first calls
cupcake_add_executable()
with the object's .name
string property,
passing PRIVATE
if the object has a .private
Boolean property
that is true
.
Then it calls target_link_libraries()
for each value in the object's .links
array property.
Each link takes one of two forms.
If it is a string, then cupcake_add_executables()
calls
target_link_libraries()
with it as the name of the linked target
and PUBLIC
as the scope.
If it is an object, then cupcake_add_executables()
calls
target_link_libraries()
with its .target
string property
as the name of the linked target and
its optional .scope
string property (default value PUBLIC
) as the scope.
{
"executables": [
{ "name": "x", "links": ["a::a"] },
{ "name": "y", "links": ["b::b", { "target": "c::c", "scope": "PRIVATE" }
]
}
def cupcake_add_executables():
metadata = json.parse('cupcake.json')
for executable in metadata.get('executables', []):
target = cupcake_add_executable(
executable['name'], PRIVATE if executable['private'] else None
)
for link in executable.get('links', []):
if type(link) == str:
target_link_libraries(target, PUBLIC, link)
else:
target_link_libraries(target, link.get('scope', PUBLIC), link['target'])
cupcake_add_tests()
Add targets for all tests in the project.
For each object in the .tests
array of cupcake.json
,
cupcake_add_tests()
first calls
cupcake_add_test()
with the object's .name
string property.
Then it calls target_link_libraries()
for each value in the object's .links
array property.
Each link takes one of two forms.
If it is a string, then cupcake_add_tests()
calls
target_link_libraries()
with it as the name of the linked target
and PUBLIC
as the scope.
If it is an object, then cupcake_add_tests()
calls
target_link_libraries()
with its .target
string property
as the name of the linked target and
its optional .scope
string property (default value PUBLIC
) as the scope.
{
"tests": [
{ "name": "x", "links": ["a::a"] },
{ "name": "y", "links": ["b::b", { "target": "c::c", "scope": "PRIVATE" }
]
}
def cupcake_add_tests():
metadata = json.parse('cupcake.json')
for test in metadata.get('tests', []):
target = cupcake_add_test(test['name'])
for link in test.get('links', []):
if type(link) == str:
target_link_libraries(target, PUBLIC, link)
else:
target_link_libraries(target, link.get('scope', PUBLIC), link['target'])
Footnotes
-
The
CMakeDeps
generator will not generate a package configuration file for a tool requirement. ↩ -
If you ever define an inline function in a public header that either (a) has its address taken or (b) defines a static variable, then you will need to make inlined functions visible to ensure that different translation units that see that definition resolve its addresses in the same way. ↩
-
An environment variable must be used because
cmake --build
does not forward any command-line arguments. ↩