Imported Upstream version 2.1.10
[platform/upstream/libevent.git] / cmake / CheckFunctionExistsEx.cmake
1 # - Check if a C function can be linked
2 # CHECK_FUNCTION_EXISTS(<function> <variable>)
3 #
4 # Check that the <function> is provided by libraries on the system and
5 # store the result in a <variable>.  This does not verify that any
6 # system header file declares the function, only that it can be found
7 # at link time (considure using CheckSymbolExists).
8 #
9 # The following variables may be set before calling this macro to
10 # modify the way the check is run:
11 #
12 #  CMAKE_REQUIRED_FLAGS = string of compile command line flags
13 #  CMAKE_REQUIRED_DEFINITIONS = list of macros to define (-DFOO=bar)
14 #  CMAKE_REQUIRED_INCLUDES = list of include directories
15 #  CMAKE_REQUIRED_LIBRARIES = list of libraries to link
16
17 #=============================================================================
18 # Copyright 2002-2011 Kitware, Inc.
19 #
20 # Distributed under the OSI-approved BSD License (the "License");
21 # see accompanying file Copyright.txt for details.
22 #
23 # This software is distributed WITHOUT ANY WARRANTY; without even the
24 # implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
25 # See the License for more information.
26 #=============================================================================
27 # (To distribute this file outside of CMake, substitute the full
28 #  License text for the above reference.)
29
30 MACRO(CHECK_FUNCTION_EXISTS_EX FUNCTION VARIABLE)
31   IF(${VARIABLE} MATCHES "^${VARIABLE}$")
32     SET(MACRO_CHECK_FUNCTION_DEFINITIONS 
33       "-DCHECK_FUNCTION_EXISTS=${FUNCTION} ${CMAKE_REQUIRED_FLAGS}")
34     MESSAGE(STATUS "Looking for ${FUNCTION}")
35     IF(CMAKE_REQUIRED_LIBRARIES)
36       SET(CHECK_FUNCTION_EXISTS_ADD_LIBRARIES
37         "-DLINK_LIBRARIES:STRING=${CMAKE_REQUIRED_LIBRARIES}")
38     ELSE(CMAKE_REQUIRED_LIBRARIES)
39       SET(CHECK_FUNCTION_EXISTS_ADD_LIBRARIES)
40     ENDIF(CMAKE_REQUIRED_LIBRARIES)
41     IF(CMAKE_REQUIRED_INCLUDES)
42       SET(CHECK_FUNCTION_EXISTS_ADD_INCLUDES
43         "-DINCLUDE_DIRECTORIES:STRING=${CMAKE_REQUIRED_INCLUDES}")
44     ELSE(CMAKE_REQUIRED_INCLUDES)
45       SET(CHECK_FUNCTION_EXISTS_ADD_INCLUDES)
46     ENDIF(CMAKE_REQUIRED_INCLUDES)
47     TRY_COMPILE(${VARIABLE}
48       ${CMAKE_BINARY_DIR}
49           ${PROJECT_SOURCE_DIR}/cmake/CheckFunctionExistsEx.c
50       COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS}
51       CMAKE_FLAGS -DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_FUNCTION_DEFINITIONS}
52       "${CHECK_FUNCTION_EXISTS_ADD_LIBRARIES}"
53       "${CHECK_FUNCTION_EXISTS_ADD_INCLUDES}"
54       OUTPUT_VARIABLE OUTPUT)
55     IF(${VARIABLE})
56       SET(${VARIABLE} 1 CACHE INTERNAL "Have function ${FUNCTION}")
57       MESSAGE(STATUS "Looking for ${FUNCTION} - found")
58       FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log 
59         "Determining if the function ${FUNCTION} exists passed with the following output:\n"
60         "${OUTPUT}\n\n")
61     ELSE(${VARIABLE})
62       MESSAGE(STATUS "Looking for ${FUNCTION} - not found")
63       SET(${VARIABLE} "" CACHE INTERNAL "Have function ${FUNCTION}")
64       FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log 
65         "Determining if the function ${FUNCTION} exists failed with the following output:\n"
66         "${OUTPUT}\n\n")
67     ENDIF(${VARIABLE})
68   ENDIF()
69 ENDMACRO(CHECK_FUNCTION_EXISTS_EX)