add_module: allow include as SYSTEM (#1416)
pybind11 headers passed via the `pybind11_add_module` CMake
function can now be included as `SYSTEM` includes (`-isystem`).
This allows to set stricter (or experimental) warnings in
calling projects that might throw otherwise in headers
a user of pybind11 can not influence.
diff --git a/docs/compiling.rst b/docs/compiling.rst
index b5d6ce9..bbd7a2c 100644
--- a/docs/compiling.rst
+++ b/docs/compiling.rst
@@ -59,7 +59,7 @@
.. code-block:: cmake
pybind11_add_module(<name> [MODULE | SHARED] [EXCLUDE_FROM_ALL]
- [NO_EXTRAS] [THIN_LTO] source1 [source2 ...])
+ [NO_EXTRAS] [SYSTEM] [THIN_LTO] source1 [source2 ...])
This function behaves very much like CMake's builtin ``add_library`` (in fact,
it's a wrapper function around that command). It will add a library target
@@ -86,6 +86,10 @@
given, they will always be disabled, even in ``Release`` mode. However, this
will result in code bloat and is generally not recommended.
+By default, pybind11 and Python headers will be included with ``-I``. In order
+to include pybind11 as system library, e.g. to avoid warnings in downstream
+code with warn-levels outside of pybind11's scope, set the option ``SYSTEM``.
+
As stated above, LTO is enabled by default. Some newer compilers also support
different flavors of LTO such as `ThinLTO`_. Setting ``THIN_LTO`` will cause
the function to prefer this flavor if available. The function falls back to
diff --git a/tools/pybind11Tools.cmake b/tools/pybind11Tools.cmake
index 52a70c2..6515f27 100644
--- a/tools/pybind11Tools.cmake
+++ b/tools/pybind11Tools.cmake
@@ -110,10 +110,10 @@
# Build a Python extension module:
# pybind11_add_module(<name> [MODULE | SHARED] [EXCLUDE_FROM_ALL]
-# [NO_EXTRAS] [THIN_LTO] source1 [source2 ...])
+# [NO_EXTRAS] [SYSTEM] [THIN_LTO] source1 [source2 ...])
#
function(pybind11_add_module target_name)
- set(options MODULE SHARED EXCLUDE_FROM_ALL NO_EXTRAS THIN_LTO)
+ set(options MODULE SHARED EXCLUDE_FROM_ALL NO_EXTRAS SYSTEM THIN_LTO)
cmake_parse_arguments(ARG "${options}" "" "" ${ARGN})
if(ARG_MODULE AND ARG_SHARED)
@@ -130,7 +130,11 @@
add_library(${target_name} ${lib_type} ${exclude_from_all} ${ARG_UNPARSED_ARGUMENTS})
- target_include_directories(${target_name}
+ if(ARG_SYSTEM)
+ set(inc_isystem SYSTEM)
+ endif()
+
+ target_include_directories(${target_name} ${inc_isystem}
PRIVATE ${PYBIND11_INCLUDE_DIR} # from project CMakeLists.txt
PRIVATE ${pybind11_INCLUDE_DIR} # from pybind11Config
PRIVATE ${PYTHON_INCLUDE_DIRS})