CMakeLists.txt.em: Reduce boilerplate in install(TARGETS for library

[traversaro]

Description

Since CMake 3.14, the install(TARGETS signature had default install destination that work well, without requiring for the user the need to set any boilerplate (see https://cmake.org/cmake/help/v3.14/command/install.html#installing-targets). As since #969 the minimum version of CMake is 3.16, we can remove all the DESTINATION arguments from the library install(TARGETS call, and the libraries will still be installed in the correct location.

Note that the install(TARGETS call that install the node executable will still keep its DESTINATION arguments, as in that case the DESTINATION is non-standard.

Is this user-facing behavior change?

The generated CMakeLists.txt will change from containing:

install(
  TARGETS <cpp_library_name>
  EXPORT export_<project_name>
  ARCHIVE DESTINATION lib
  LIBRARY DESTINATION lib
  RUNTIME DESTINATION bin)

to:

install(
  TARGETS <cpp_library_name>
  EXPORT export_<project_name>
)

while keeping the same behavior, reducing the generated boilerplate.

Did you use Generative AI?

No.

Additional Information

Triggered by ros-misc-utilities/apriltag_detector#7 .

[fujitatomoya]

lgtm but can we also apply the same change to

ros2cli/ros2pkg/ros2pkg/resource/ament_cmake/CMakeLists.txt.em

Lines 50 to 52 in c24da0a

	ARCHIVE DESTINATION lib
	LIBRARY DESTINATION lib
	RUNTIME DESTINATION bin

?

[traversaro]

lgtm but can we also apply the same change to

ros2cli/ros2pkg/ros2pkg/resource/ament_cmake/CMakeLists.txt.em

Lines 50 to 52 in c24da0a

	ARCHIVE DESTINATION lib
	LIBRARY DESTINATION lib
	RUNTIME DESTINATION bin

?

That file still have a minimum CMake version of 3.8, see

ros2cli/ros2pkg/ros2pkg/resource/ament_cmake/CMakeLists.txt.em

Line 1 in c24da0a

cmake_minimum_required(VERSION 3.8)

. If that can also be raised to 3.16, then I think it make sense to do the same change there.

[fujitatomoya]

Ah I see then we can go ahead with this change for now.

note: i think i am gonna have to to align the minimum CMake version for all packages together, and then apply this same change with them.

[fujitatomoya]

Pulls: #1056
Gist: https://gist.githubusercontent.com/fujitatomoya/e32bd71a2bffdf25c30f19a52be5e838/raw/c3728ee3998630fa4f2f752dff592022b6f530ae/ros2.repos
BUILD args: --packages-above-and-dependencies ros2pkg
TEST args: --packages-above ros2pkg
ROS Distro: rolling
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/16217

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