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# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file LICENSE.rst or https://cmake.org/licensing for details.
#[=======================================================================[.rst:
FindBacktrace
-------------
Finds `backtrace(3) <https://man7.org/linux/man-pages/man3/backtrace.3.html>`_,
a library that provides functions for application self-debugging.
This module checks whether ``backtrace(3)`` is supported, either through the
standard C library (``libc``), or a separate library.
Imported Targets
^^^^^^^^^^^^^^^^
.. versionadded:: 3.30
This module provides the following :ref:`Imported Targets`:
``Backtrace::Backtrace``
An interface library encapsulating the usage requirements of Backtrace. This
target is available only when Backtrace is found.
Result Variables
^^^^^^^^^^^^^^^^
This module defines the following variables:
``Backtrace_INCLUDE_DIRS``
The include directories needed to use ``backtrace(3)`` header.
``Backtrace_LIBRARIES``
The libraries (linker flags) needed to use ``backtrace(3)``, if any.
``Backtrace_FOUND``
Boolean indicating whether the ``backtrace(3)`` support is available.
Cache Variables
^^^^^^^^^^^^^^^
The following cache variables are also available to set or use:
``Backtrace_HEADER``
The header file needed for ``backtrace(3)``. This variable allows dynamic
usage of the header in the project code. It can also be overridden by the
user.
``Backtrace_LIBRARY``
The external library providing backtrace, if any.
``Backtrace_INCLUDE_DIR``
The directory holding the ``backtrace(3)`` header.
Examples
^^^^^^^^
Finding Backtrace and linking it to a project target as of CMake 3.30:
.. code-block:: cmake
:caption: CMakeLists.txt
find_package(Backtrace)
target_link_libraries(app PRIVATE Backtrace::Backtrace)
The ``Backtrace_HEADER`` variable can be used, for example, in a configuration
header file created by :command:`configure_file`:
.. code-block:: cmake
:caption: CMakeLists.txt
add_library(app app.c)
find_package(Backtrace)
target_link_libraries(app PRIVATE Backtrace::Backtrace)
configure_file(config.h.in config.h)
.. code-block:: c
:caption: config.h.in
#cmakedefine01 Backtrace_FOUND
#if Backtrace_FOUND
# include <@Backtrace_HEADER@>
#endif
.. code-block:: c
:caption: app.c
#include "config.h"
If the project needs to support CMake 3.29 or earlier, the imported target can
be defined manually:
.. code-block:: cmake
:caption: CMakeLists.txt
find_package(Backtrace)
if(Backtrace_FOUND AND NOT TARGET Backtrace::Backtrace)
add_library(Backtrace::Backtrace INTERFACE IMPORTED)
set_target_properties(
Backtrace::Backtrace
PROPERTIES
INTERFACE_LINK_LIBRARIES "${Backtrace_LIBRARIES}"
INTERFACE_INCLUDE_DIRECTORIES "${Backtrace_INCLUDE_DIRS}"
)
endif()
target_link_libraries(app PRIVATE Backtrace::Backtrace)
#]=======================================================================]
include(CMakePushCheckState)
include(CheckSymbolExists)
include(FindPackageHandleStandardArgs)
# List of variables to be provided to find_package_handle_standard_args()
set(_Backtrace_STD_ARGS Backtrace_INCLUDE_DIR)
if(Backtrace_HEADER)
set(_Backtrace_HEADER_TRY "${Backtrace_HEADER}")
else()
set(_Backtrace_HEADER_TRY "execinfo.h")
endif()
find_path(Backtrace_INCLUDE_DIR "${_Backtrace_HEADER_TRY}")
set(Backtrace_INCLUDE_DIRS ${Backtrace_INCLUDE_DIR})
if (NOT DEFINED Backtrace_LIBRARY)
# First, check if we already have backtrace(), e.g., in libc
cmake_push_check_state(RESET)
set(CMAKE_REQUIRED_INCLUDES ${Backtrace_INCLUDE_DIRS})
set(CMAKE_REQUIRED_QUIET ${Backtrace_FIND_QUIETLY})
check_symbol_exists("backtrace" "${_Backtrace_HEADER_TRY}" _Backtrace_SYM_FOUND)
cmake_pop_check_state()
endif()
if(_Backtrace_SYM_FOUND)
# Avoid repeating the message() call below each time CMake is run.
if(NOT Backtrace_FIND_QUIETLY AND NOT DEFINED Backtrace_LIBRARY)
message(STATUS "backtrace facility detected in default set of libraries")
endif()
set(Backtrace_LIBRARY "" CACHE FILEPATH "Library providing backtrace(3), empty for default set of libraries")
else()
# Check for external library, for non-glibc systems
if(Backtrace_INCLUDE_DIR)
# OpenBSD has libbacktrace renamed to libexecinfo
find_library(Backtrace_LIBRARY "execinfo")
else() # respect user wishes
set(_Backtrace_HEADER_TRY "backtrace.h")
find_path(Backtrace_INCLUDE_DIR ${_Backtrace_HEADER_TRY})
find_library(Backtrace_LIBRARY "backtrace")
endif()
# Prepend list with library path as it's more common practice
set(_Backtrace_STD_ARGS Backtrace_LIBRARY ${_Backtrace_STD_ARGS})
endif()
set(Backtrace_LIBRARIES ${Backtrace_LIBRARY})
set(Backtrace_HEADER "${_Backtrace_HEADER_TRY}" CACHE STRING "Header providing backtrace(3) facility")
find_package_handle_standard_args(Backtrace REQUIRED_VARS ${_Backtrace_STD_ARGS})
mark_as_advanced(Backtrace_HEADER Backtrace_INCLUDE_DIR Backtrace_LIBRARY)
if(Backtrace_FOUND AND NOT TARGET Backtrace::Backtrace)
if(Backtrace_LIBRARY)
add_library(Backtrace::Backtrace UNKNOWN IMPORTED)
set_property(TARGET Backtrace::Backtrace PROPERTY IMPORTED_LOCATION "${Backtrace_LIBRARY}")
else()
add_library(Backtrace::Backtrace INTERFACE IMPORTED)
target_link_libraries(Backtrace::Backtrace INTERFACE ${Backtrace_LIBRARIES})
endif()
target_include_directories(Backtrace::Backtrace INTERFACE ${Backtrace_INCLUDE_DIRS})
endif()
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