Cmake usage base summary

target_include_directories What to do ？
Specify the path of the header file contained in the target .

Inside INTERFACE|PUBLIC|PRIVATE What's the effect ？
INTERFACE：target The corresponding header file uses
PRIVATE：target The corresponding source file uses
PUBLIC：target Corresponding header file 、 Source files are used

Example ：
target_include_directories(${LIBRARY_NAME}
    PUBLIC
        $<INSTALL_INTERFACE:include>
        ${XXX_INCLUDE_DIR}
    PRIVATE
        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
)

project() What is it? ？
project Is used to specify the cmake The name of the project , actually , It can also specify cmake Version number of the project (VERSION keyword )、 A short description (DESCRIPTION keyword )、 Home page URL(HOMEPAGE_URL keyword ) And the language used to compile the project
(LANGUAGES keyword )

Example ：
project(XXX LANGUAGES CXX VERSION 0.1.0)

add_library() What is it? ？
add_library The command is used to add a target library to the project using the specified source file （ Generate library files ）, There are mainly the following forms .

add_library(<name> [STATIC | SHARED | MODULE]
            [EXCLUDE_FROM_ALL]
            [<source>...])

Add a from source The target name built from the files listed in the list is name The library of ,name It has to be globally unique .( The source file for building the library can be directly specified , It can also be used later target_sources() Appoint .）
STATIC( Static library ) SHARED( Dynamic library ) MODULE( Module library ) Used to specify the type of Library . Use STATIC Build and generate static libraries (name.a), Use SHARED Build and generate dynamic libraries (name.so).

Example ：
add_library(${LIBRARY_NAME} SHARED
    ${SRC_LIST}
)

aux_source_directory() What is it? ？
Collect all in the specified path <dir> The file name of the source file under , Store the output result list in the specified variable <variable> in .
aux_source_directory(<dir> <variable>)
This command is intended for projects instantiated with explicit templates . Template instantiation files can be stored in Templates Subdirectory , And use this command to automatically collect , To avoid manually listing all instantiations .

install() What is it? ？
install Used to specify rules to run at installation time . It can be used to install a lot of content , Can include target binary 、 Dynamic library 、 Static libraries and files 、 Catalog 、 Script etc.
（ perform make install when , The specified header file , Install the library to the specified location .）

TARGETS：TARGET It can be many kinds of target files , The most common is through ADD_EXECUTABLE perhaps ADD_LIBRARY Defined target file , You can execute binary 、 Dynamic library 、 Static library .
ARCHIVE     Static library     ${CMAKE_INSTALL_LIBDIR}    lib
LIBRARY     Dynamic library     ${CMAKE_INSTALL_LIBDIR}    lib
RUNTIME     Executable binary     ${CMAKE_INSTALL_BINDIR}    bin
PUBLIC_HEADER     Associated with the library PUBLIC The header file     ${CMAKE_INSTALL_INCLUDEDIR}    include
PRIVATE_HEADER     Associated with the library PRIVATE The header file     ${CMAKE_INSTALL_INCLUDEDIR}    include

In order to conform to the general default installation path , If set DESTINATION Parameters , It is recommended to configure the folder under the installation directory variable .

The following example will ： Executable binary myrun The installation to ${CMAKE_INSTALL_BINDIR} Catalog , Dynamic library libmylib.so The installation to ${CMAKE_INSTALL_LIBDIR} Catalog , Static library libmystaticlib.a The installation to ${CMAKE_INSTALL_LIBDIR} Catalog .

Example 1：
INSTALL(TARGETS myrun mylib mystaticlib
       RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
       LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
       ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
)

Example 2：
install(TARGETS ${LIBRARY_NAME} EXPORT ${PROJECT_NAME}-targets
    ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
)

Directory installation , Use DIRECTORY, This command installs the contents of one or more directories to a given destination , The directory structure is copied to the target location one by one . The last component of each directory name is appended to the target directory , But you can use a trailing slash to avoid this , Because it leaves the last component blank .
DIRECTORY If it is abc signify abc This directory will be installed in the target path ,abc/ signify abc The contents of this directory will be installed in the target path , and abc The directory itself is not installed . namely , If the directory name is not / ending , Then this directory will be installed as abc, If the directory name is / ending , Represents the installation of the contents of this directory to the target path , But not the directory itself .

Example 3：
install(DIRECTORY include/
    DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
    COMPONENT dev
)