1# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
2# file Copyright.txt or https://cmake.org/licensing for details.
3
4#[=======================================================================[.rst:
5FindBacktrace
6-------------
7
8Find provider for `backtrace(3) <http://man7.org/linux/man-pages/man3/backtrace.3.html>`__.
9
10Checks if OS supports ``backtrace(3)`` via either ``libc`` or custom library.
11This module defines the following variables:
12
13``Backtrace_HEADER``
14  The header file needed for ``backtrace(3)``. Cached.
15  Could be forcibly set by user.
16``Backtrace_INCLUDE_DIRS``
17  The include directories needed to use ``backtrace(3)`` header.
18``Backtrace_LIBRARIES``
19  The libraries (linker flags) needed to use ``backtrace(3)``, if any.
20``Backtrace_FOUND``
21  Is set if and only if ``backtrace(3)`` support detected.
22
23The following cache variables are also available to set or use:
24
25``Backtrace_LIBRARY``
26  The external library providing backtrace, if any.
27``Backtrace_INCLUDE_DIR``
28  The directory holding the ``backtrace(3)`` header.
29
30Typical usage is to generate of header file using :command:`configure_file`
31with the contents like the following::
32
33 #cmakedefine01 Backtrace_FOUND
34 #if Backtrace_FOUND
35 # include <${Backtrace_HEADER}>
36 #endif
37
38And then reference that generated header file in actual source.
39#]=======================================================================]
40
41include(CMakePushCheckState)
42include(CheckSymbolExists)
43include(${CMAKE_CURRENT_LIST_DIR}/FindPackageHandleStandardArgs.cmake)
44
45# List of variables to be provided to find_package_handle_standard_args()
46set(_Backtrace_STD_ARGS Backtrace_INCLUDE_DIR)
47
48if(Backtrace_HEADER)
49  set(_Backtrace_HEADER_TRY "${Backtrace_HEADER}")
50else(Backtrace_HEADER)
51  set(_Backtrace_HEADER_TRY "execinfo.h")
52endif(Backtrace_HEADER)
53
54find_path(Backtrace_INCLUDE_DIR "${_Backtrace_HEADER_TRY}")
55set(Backtrace_INCLUDE_DIRS ${Backtrace_INCLUDE_DIR})
56
57if (NOT DEFINED Backtrace_LIBRARY)
58  # First, check if we already have backtrace(), e.g., in libc
59  cmake_push_check_state(RESET)
60  set(CMAKE_REQUIRED_INCLUDES ${Backtrace_INCLUDE_DIRS})
61  set(CMAKE_REQUIRED_QUIET ${Backtrace_FIND_QUIETLY})
62  check_symbol_exists("backtrace" "${_Backtrace_HEADER_TRY}" _Backtrace_SYM_FOUND)
63  cmake_pop_check_state()
64endif()
65
66if(_Backtrace_SYM_FOUND)
67  # Avoid repeating the message() call below each time CMake is run.
68  if(NOT Backtrace_FIND_QUIETLY AND NOT DEFINED Backtrace_LIBRARY)
69    message(STATUS "backtrace facility detected in default set of libraries")
70  endif()
71  set(Backtrace_LIBRARY "" CACHE FILEPATH "Library providing backtrace(3), empty for default set of libraries")
72else()
73  # Check for external library, for non-glibc systems
74  if(Backtrace_INCLUDE_DIR)
75    # OpenBSD has libbacktrace renamed to libexecinfo
76    find_library(Backtrace_LIBRARY "execinfo")
77  else()     # respect user wishes
78    set(_Backtrace_HEADER_TRY "backtrace.h")
79    find_path(Backtrace_INCLUDE_DIR ${_Backtrace_HEADER_TRY})
80    find_library(Backtrace_LIBRARY "backtrace")
81  endif()
82
83  # Prepend list with library path as it's more common practice
84  set(_Backtrace_STD_ARGS Backtrace_LIBRARY ${_Backtrace_STD_ARGS})
85endif()
86
87set(Backtrace_LIBRARIES ${Backtrace_LIBRARY})
88set(Backtrace_HEADER "${_Backtrace_HEADER_TRY}" CACHE STRING "Header providing backtrace(3) facility")
89
90find_package_handle_standard_args(Backtrace FOUND_VAR Backtrace_FOUND REQUIRED_VARS ${_Backtrace_STD_ARGS})
91mark_as_advanced(Backtrace_HEADER Backtrace_INCLUDE_DIR Backtrace_LIBRARY)
92