add_library¶
Add a library to the project using the specified source files.
Normal Libraries¶
- add_library(<name> [<type>] [EXCLUDE_FROM_ALL] <sources>...)¶
- Add a library target called - <name>to be built from the source files listed in the command invocation.- The optional - <type>specifies the type of library to be created:- STATIC
- An archive of object files for use when linking other targets. 
- SHARED
- A dynamic library that may be linked by other targets and loaded at runtime. 
- MODULE
- A plugin that may not be linked by other targets, but may be dynamically loaded at runtime using dlopen-like functionality. 
 - If no - <type>is given the default is- STATICor- SHAREDbased on the value of the- BUILD_SHARED_LIBSvariable.- The options are: - EXCLUDE_FROM_ALL
- Set the - EXCLUDE_FROM_ALLtarget property automatically. See documentation of that target property for details.
 
The <name> corresponds to the logical target name and must be globally
unique within a project.  The actual file name of the library built is
constructed based on conventions of the native platform (such as
lib<name>.a or <name>.lib).
Added in version 3.1: Source arguments to add_library may use "generator expressions" with
the syntax $<...>.  See the cmake-generator-expressions(7)
manual for available expressions.
Added in version 3.11: The source files can be omitted if they are added later using
target_sources().
For SHARED and MODULE libraries the
POSITION_INDEPENDENT_CODE target
property is set to ON automatically.
A SHARED library may be marked with the FRAMEWORK
target property to create an macOS Framework.
Added in version 3.8: A STATIC library may be marked with the FRAMEWORK
target property to create a static Framework.
If a library does not export any symbols, it must not be declared as a
SHARED library.  For example, a Windows resource DLL or a managed C++/CLI
DLL that exports no unmanaged symbols would need to be a MODULE library.
This is because CMake expects a SHARED library to always have an
associated import library on Windows.
By default the library file will be created in the build tree directory
corresponding to the source tree directory in which the command was
invoked.  See documentation of the ARCHIVE_OUTPUT_DIRECTORY,
LIBRARY_OUTPUT_DIRECTORY, and
RUNTIME_OUTPUT_DIRECTORY target properties to change this
location.  See documentation of the OUTPUT_NAME target
property to change the <name> part of the final file name.
See the cmake-buildsystem(7) manual for more on defining
buildsystem properties.
See also HEADER_FILE_ONLY on what to do if some sources are
pre-processed, and you want to have the original sources reachable from
within IDE.
Changed in version 3.30: On platforms that do not support shared libraries, add_library
now fails on calls creating SHARED libraries instead of
automatically converting them to STATIC libraries as before.
See policy CMP0164.
Object Libraries¶
- add_library(<name> OBJECT <sources>...)¶
- Add an Object Library to compile source files without archiving or linking their object files into a library. 
Other targets created by add_library or add_executable()
may reference the objects using an expression of the
form $<TARGET_OBJECTS:objlib> as a source, where
objlib is the object library name.  For example:
add_library(... $<TARGET_OBJECTS:objlib> ...)
add_executable(... $<TARGET_OBJECTS:objlib> ...)
will include objlib's object files in a library and an executable
along with those compiled from their own sources.  Object libraries
may contain only sources that compile, header files, and other files
that would not affect linking of a normal library (e.g. .txt).
They may contain custom commands generating such sources, but not
PRE_BUILD, PRE_LINK, or POST_BUILD commands.  Some native build
systems (such as Xcode) may not like targets that have only object files, so
consider adding at least one real source file to any target that references
$<TARGET_OBJECTS:objlib>.
Added in version 3.12: Object libraries can be linked to with target_link_libraries().
Interface Libraries¶
- add_library(<name> INTERFACE)¶
- Add an Interface Library target that may specify usage requirements for dependents but does not compile sources and does not produce a library artifact on disk. - An interface library with no source files is not included as a target in the generated buildsystem. However, it may have properties set on it and it may be installed and exported. Typically, - INTERFACE_*properties are populated on an interface target using the commands:- and then it is used as an argument to - target_link_libraries()like any other target.- Added in version 3.15: An interface library can have - PUBLIC_HEADERand- PRIVATE_HEADERproperties. The headers specified by those properties can be installed using the- install(TARGETS)command.
- add_library(<name> INTERFACE [EXCLUDE_FROM_ALL] <sources>...)¶
- Added in version 3.19. - Add an Interface Library target with source files (in addition to usage requirements and properties as documented by the - above signature). Source files may be listed directly in the- add_librarycall or added later by calls to- target_sources()with the- PRIVATEor- PUBLICkeywords.- If an interface library has source files (i.e. the - SOURCEStarget property is set), or header sets (i.e. the- HEADER_SETStarget property is set), it will appear in the generated buildsystem as a build target much like a target defined by the- add_custom_target()command. It does not compile any sources, but does contain build rules for custom commands created by the- add_custom_command()command.- The options are: - EXCLUDE_FROM_ALL
- Set the - EXCLUDE_FROM_ALLtarget property automatically. See documentation of that target property for details.
 - Note - In most command signatures where the - INTERFACEkeyword appears, the items listed after it only become part of that target's usage requirements and are not part of the target's own settings. However, in this signature of- add_library, the- INTERFACEkeyword refers to the library type only. Sources listed after it in the- add_librarycall are- PRIVATEto the interface library and do not appear in its- INTERFACE_SOURCEStarget property.
Imported Libraries¶
- add_library(<name> <type> IMPORTED [GLOBAL])¶
- Add an IMPORTED library target called - <name>. The target name may be referenced like any target built within the project, except that by default it is visible only in the directory in which it is created, and below.- The - <type>must be one of:- STATIC,- SHARED,- MODULE,- UNKNOWN
- References a library file located outside the project. The - IMPORTED_LOCATIONtarget property (or its per-configuration variant- IMPORTED_LOCATION_<CONFIG>) specifies the location of the main library file on disk:- For a - SHAREDlibrary on most non-Windows platforms, the main library file is the- .soor- .dylibfile used by both linkers and dynamic loaders. If the referenced library file has a- SONAME(or on macOS, has a- LC_ID_DYLIBstarting in- @rpath/), the value of that field should be set in the- IMPORTED_SONAMEtarget property. If the referenced library file does not have a- SONAME, but the platform supports it, then the- IMPORTED_NO_SONAMEtarget property should be set.
- For a - SHAREDlibrary on Windows, the- IMPORTED_IMPLIBtarget property (or its per-configuration variant- IMPORTED_IMPLIB_<CONFIG>) specifies the location of the DLL import library file (- .libor- .dll.a) on disk, and the- IMPORTED_LOCATIONis the location of the- .dllruntime library (and is optional, but needed by the- TARGET_RUNTIME_DLLSgenerator expression).
 - Additional usage requirements may be specified in - INTERFACE_*properties.- An - UNKNOWNlibrary type is typically only used in the implementation of Find Modules. It allows the path to an imported library (often found using the- find_library()command) to be used without having to know what type of library it is. This is especially useful on Windows where a static library and a DLL's import library both have the same file extension.
- OBJECT
- References a set of object files located outside the project. The - IMPORTED_OBJECTStarget property (or its per-configuration variant- IMPORTED_OBJECTS_<CONFIG>) specifies the locations of object files on disk. Additional usage requirements may be specified in- INTERFACE_*properties.
- INTERFACE
- Does not reference any library or object files on disk, but may specify usage requirements in - INTERFACE_*properties.
 - The options are: - GLOBAL
- Make the target name globally visible. 
 
No rules are generated to build imported targets, and the IMPORTED
target property is True.  Imported libraries are useful for convenient
reference from commands like target_link_libraries().
Details about the imported library are specified by setting properties whose
names begin in IMPORTED_ and INTERFACE_.  See documentation of
such properties for more information.
Alias Libraries¶
- add_library(<name> ALIAS <target>)¶
- Creates an Alias Target, such that - <name>can be used to refer to- <target>in subsequent commands. The- <name>does not appear in the generated buildsystem as a make target. The- <target>may not be an- ALIAS.
Added in version 3.11: An ALIAS can target a GLOBAL Imported Target
Added in version 3.18: An ALIAS can target a non-GLOBAL Imported Target. Such alias is
scoped to the directory in which it is created and below.
The ALIAS_GLOBAL target property can be used to check if the
alias is global or not.
ALIAS targets can be used as linkable targets and as targets to
read properties from.  They can also be tested for existence with the
regular if(TARGET) subcommand.  The <name> may not be used
to modify properties of <target>, that is, it may not be used as the
operand of set_property(), set_target_properties(),
target_link_libraries() etc.  An ALIAS target may not be
installed or exported.
