libssh2/cmake/CheckFunctionExistsMayNeedL...

81 lines
3.1 KiB
CMake

# Copyright (c) 2014 Alexander Lamaison <alexander.lamaison@gmail.com>
#
# Redistribution and use in source and binary forms,
# with or without modification, are permitted provided
# that the following conditions are met:
#
# Redistributions of source code must retain the above
# copyright notice, this list of conditions and the
# following disclaimer.
#
# Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following
# disclaimer in the documentation and/or other materials
# provided with the distribution.
#
# Neither the name of the copyright holder nor the names
# of any other contributors may be used to endorse or
# promote products derived from this software without
# specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
# CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
# INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
# USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
# OF SUCH DAMAGE.
# - check_function_exists_maybe_need_library(<function> <var> [lib1 ... libn])
#
# Check if function is available for linking, first without extra libraries, and
# then, if not found that way, linking in each optional library as well. This
# function is similar to autotools AC_SEARCH_LIBS.
#
# If the function if found, this will define <var>.
#
# If the function was only found by linking in an additional library, this
# will define NEED_LIB_LIBX, where LIBX is the one of lib1 to libn that
# makes the function available, in uppercase.
#
# 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
#
include(CheckFunctionExists)
include(CheckLibraryExists)
function(check_function_exists_may_need_library function variable)
check_function_exists(${function} ${variable})
if(NOT ${variable})
foreach(lib ${ARGN})
string(TOUPPER ${lib} UP_LIB)
# Use new variable to prevent cache from previous step shortcircuiting
# new test
check_library_exists(${lib} ${function} "" HAVE_${function}_IN_${lib})
if(HAVE_${function}_IN_${lib})
set(${variable} 1 CACHE INTERNAL
"Function ${function} found in library ${lib}")
set(NEED_LIB_${UP_LIB} 1 CACHE INTERNAL
"Need to link ${lib}")
break()
endif()
endforeach()
endif()
endfunction()