INTERFACE_INCLUDE_DIRECTORIES¶
List of public include directories requirements for a library.
Targets may populate this property to publish the include directories
required to compile against the headers for the target. The target_include_directories()
command populates this property with values given to the PUBLIC
and
INTERFACE
keywords. Projects may also get and set the property directly.
When target dependencies are specified using target_link_libraries()
,
CMake will read this property from all target dependencies to determine the
build properties of the consumer.
Contents of INTERFACE_INCLUDE_DIRECTORIES
may use "generator expressions"
with the syntax $<...>
. See the cmake-generator-expressions(7)
manual for available expressions. See the cmake-buildsystem(7)
-manual for more on defining buildsystem properties.
Include directories usage requirements commonly differ between the build-tree
and the install-tree. The BUILD_INTERFACE
and INSTALL_INTERFACE
generator expressions can be used to describe separate usage requirements
based on the usage location. Relative paths are allowed within the
INSTALL_INTERFACE
expression and are interpreted relative to the
installation prefix. For example:
target_include_directories(mylib INTERFACE
$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include/mylib>
$<INSTALL_INTERFACE:include/mylib> # <prefix>/include/mylib
)
Creating Relocatable Packages¶
Note that it is not advisable to populate the INSTALL_INTERFACE
of
the INTERFACE_INCLUDE_DIRECTORIES
of a target with absolute paths to the include
directories of dependencies. That would hard-code into installed packages
the include directory paths for dependencies
as found on the machine the package was made on.
The INSTALL_INTERFACE
of the INTERFACE_INCLUDE_DIRECTORIES
is only
suitable for specifying the required include directories for headers
provided with the target itself, not those provided by the transitive
dependencies listed in its INTERFACE_LINK_LIBRARIES
target
property. Those dependencies should themselves be targets that specify
their own header locations in INTERFACE_INCLUDE_DIRECTORIES
.
See the Creating Relocatable Packages section of the
cmake-packages(7)
manual for discussion of additional care
that must be taken when specifying usage requirements while creating
packages for redistribution.