summaryrefslogtreecommitdiffstats
path: root/Modules/CheckSymbolExists.cmake
blob: c4dff3faaf8c3464bc87545fc4c5fb5e9044639b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
#.rst:
# CheckSymbolExists
# -----------------
#
# Check if a symbol exists as a function, variable, or macro
#
# CHECK_SYMBOL_EXISTS(<symbol> <files> <variable>)
#
# Check that the <symbol> is available after including given header
# <files> and store the result in a <variable>.  Specify the list of
# files in one argument as a semicolon-separated list.
# <variable> will be created as an internal cache variable.
#
# If the header files define the symbol as a macro it is considered
# available and assumed to work.  If the header files declare the symbol
# as a function or variable then the symbol must also be available for
# linking.  If the symbol is a type or enum value it will not be
# recognized (consider using CheckTypeSize or CheckCSourceCompiles).  If
# the check needs to be done in C++, consider using
# CHECK_CXX_SYMBOL_EXISTS(), which does the same as
# CHECK_SYMBOL_EXISTS(), but in C++.
#
# The following variables may be set before calling this macro to modify
# the way the check is run:
#
# ::
#
#   CMAKE_REQUIRED_FLAGS = string of compile command line flags
#   CMAKE_REQUIRED_DEFINITIONS = list of macros to define (-DFOO=bar)
#   CMAKE_REQUIRED_INCLUDES = list of include directories
#   CMAKE_REQUIRED_LIBRARIES = list of libraries to link
#   CMAKE_REQUIRED_QUIET = execute quietly without messages

#=============================================================================
# Copyright 2003-2011 Kitware, Inc.
#
# Distributed under the OSI-approved BSD License (the "License");
# see accompanying file Copyright.txt for details.
#
# This software is distributed WITHOUT ANY WARRANTY; without even the
# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the License for more information.
#=============================================================================
# (To distribute this file outside of CMake, substitute the full
#  License text for the above reference.)

macro(CHECK_SYMBOL_EXISTS SYMBOL FILES VARIABLE)
  if(CMAKE_C_COMPILER_LOADED)
    _CHECK_SYMBOL_EXISTS("${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.c" "${SYMBOL}" "${FILES}" "${VARIABLE}" )
  elseif(CMAKE_CXX_COMPILER_LOADED)
    _CHECK_SYMBOL_EXISTS("${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.cxx" "${SYMBOL}" "${FILES}" "${VARIABLE}" )
  else()
    message(FATAL_ERROR "CHECK_SYMBOL_EXISTS needs either C or CXX language enabled")
  endif()
endmacro()

macro(_CHECK_SYMBOL_EXISTS SOURCEFILE SYMBOL FILES VARIABLE)
  if(NOT DEFINED "${VARIABLE}" OR "x${${VARIABLE}}" STREQUAL "x${VARIABLE}")
    set(CMAKE_CONFIGURABLE_FILE_CONTENT "/* */\n")
    set(MACRO_CHECK_SYMBOL_EXISTS_FLAGS ${CMAKE_REQUIRED_FLAGS})
    if(CMAKE_REQUIRED_LIBRARIES)
      set(CHECK_SYMBOL_EXISTS_LIBS
        LINK_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
    else()
      set(CHECK_SYMBOL_EXISTS_LIBS)
    endif()
    if(CMAKE_REQUIRED_INCLUDES)
      set(CMAKE_SYMBOL_EXISTS_INCLUDES
        "-DINCLUDE_DIRECTORIES:STRING=${CMAKE_REQUIRED_INCLUDES}")
    else()
      set(CMAKE_SYMBOL_EXISTS_INCLUDES)
    endif()
    foreach(FILE ${FILES})
      set(CMAKE_CONFIGURABLE_FILE_CONTENT
        "${CMAKE_CONFIGURABLE_FILE_CONTENT}#include <${FILE}>\n")
    endforeach()
    set(CMAKE_CONFIGURABLE_FILE_CONTENT
      "${CMAKE_CONFIGURABLE_FILE_CONTENT}\nint main(int argc, char** argv)\n{\n  (void)argv;\n#ifndef ${SYMBOL}\n  return ((int*)(&${SYMBOL}))[argc];\n#else\n  (void)argc;\n  return 0;\n#endif\n}\n")

    configure_file("${CMAKE_ROOT}/Modules/CMakeConfigurableFile.in"
      "${SOURCEFILE}" @ONLY)

    if(NOT CMAKE_REQUIRED_QUIET)
      message(STATUS "Looking for ${SYMBOL}")
    endif()
    try_compile(${VARIABLE}
      ${CMAKE_BINARY_DIR}
      "${SOURCEFILE}"
      COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS}
      ${CHECK_SYMBOL_EXISTS_LIBS}
      CMAKE_FLAGS
      -DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_SYMBOL_EXISTS_FLAGS}
      "${CMAKE_SYMBOL_EXISTS_INCLUDES}"
      OUTPUT_VARIABLE OUTPUT)
    if(${VARIABLE})
      if(NOT CMAKE_REQUIRED_QUIET)
        message(STATUS "Looking for ${SYMBOL} - found")
      endif()
      set(${VARIABLE} 1 CACHE INTERNAL "Have symbol ${SYMBOL}")
      file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
        "Determining if the ${SYMBOL} "
        "exist passed with the following output:\n"
        "${OUTPUT}\nFile ${SOURCEFILE}:\n"
        "${CMAKE_CONFIGURABLE_FILE_CONTENT}\n")
    else()
      if(NOT CMAKE_REQUIRED_QUIET)
        message(STATUS "Looking for ${SYMBOL} - not found")
      endif()
      set(${VARIABLE} "" CACHE INTERNAL "Have symbol ${SYMBOL}")
      file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
        "Determining if the ${SYMBOL} "
        "exist failed with the following output:\n"
        "${OUTPUT}\nFile ${SOURCEFILE}:\n"
        "${CMAKE_CONFIGURABLE_FILE_CONTENT}\n")
    endif()
  endif()
endmacro()