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| author |  Eric Barndollar <eric@EricWBarndollar.com> | 2021-07-29 21:33:51 -0400 |
|---|---|---|
| committer |  GitHub <noreply@github.com> | 2021-07-29 21:33:51 -0400 |
| commit | ee0ebdae4a9e789b92f5abbe8573ddeeaead4864 (patch) | |
| tree | 171f8b99d3a784943abf99e104dd0bb787e86b7c /CMakeLists.txt | |
| parent | 89c531c1e0d7372e2e7029f072a35495c5447d61 (diff) | |
CMake: option to use cxx_std_11 (minimum) that propagates. (#986)
See https://github.com/abseil/abseil-cpp/issues/259 for context.
This change introduces the ABSL_PROPAGATE_CXX_STD option (default to OFF for now, though it prints a warning in CMake 2.8+ builds that a future Abseil release will default to ON). When enabled, all Abseil CMake targets will set the cxx_std_11 target meta feature (which will then propagate to targets that depend upon Abseil) rather than setting the target-level CXX_STANDARD property to CMAKE_CXX_STANDARD (which is the default value anyway), which doesn't propagate.
Updates README documentation to clarify behavior and with a different example recommendation for library projects (which should generally leave CMAKE_CXX_STANDARD to the root application project).
See https://crascit.com/2015/03/28/enabling-cxx11-in-cmake/ for a useful overview of these different CMake features surrounding C++ standard version configuration.
Diffstat (limited to 'CMakeLists.txt')
| -rw-r--r-- | CMakeLists.txt | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/CMakeLists.txt b/CMakeLists.txt index 42bcbe10..7c8bfff4 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -67,6 +67,13 @@ else() option(ABSL_ENABLE_INSTALL "Enable install rule" ON) endif() +option(ABSL_PROPAGATE_CXX_STD + "Use CMake C++ standard meta features (e.g. cxx_std_11) that propagate to targets that link to Abseil" + OFF) # TODO: Default to ON for CMake 3.8 and greater. +if((${CMAKE_VERSION} VERSION_GREATER_EQUAL 3.8) AND (NOT ABSL_PROPAGATE_CXX_STD)) + message(WARNING "A future Abseil release will default ABSL_PROPAGATE_CXX_STD to ON for CMake 3.8 and up. We recommend enabling this option to ensure your project still builds correctly.") +endif() + list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_LIST_DIR}/CMake ${CMAKE_CURRENT_LIST_DIR}/absl/copts |