curl/CMake/FindCares.cmake
Viktor Szakats f66af623cf
cmake: document -D and env build options
Extend `INSTALL-CMAKE` document with the list of available options,
a short description and default values.

The list may not be 100% complete.

There are no component boundaries in CMake, so the line is blurry
between curl options, CMake options, CMake Find modules options.
I included certain CMake options that seemed useful, and/or have
dedicated use withing curl's CMake source. But, all CMake built-in
options are usable, as documented upstream in CMake.

The naming of the options has a heritage and the inconsistencies with
it, including a lack of clear namespace. This may be subject to future
updates, also after figuring out which name has special meaning within
CMake and/or CMake projects out of unwritten convention or something
more tangible.

CMake allows to initialize any internal variable via `-D`. This may be
useful to pre-initialize/override feature check results. The list
doesn't contain these, and they remain officially undocumented.

Also:
- make adjustments to keep the spellchecker happy.
- retrofit description changes to the cmake sources.
- stop documenting deprecated `Find*` variables.

Reported-by: Daniel Stenberg
Fixes https://github.com/curl/curl/discussions/14885
Closes #15388
2024-10-24 23:06:40 +02:00

91 lines
3.1 KiB
CMake

#***************************************************************************
# _ _ ____ _
# Project ___| | | | _ \| |
# / __| | | | |_) | |
# | (__| |_| | _ <| |___
# \___|\___/|_| \_\_____|
#
# Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at https://curl.se/docs/copyright.html.
#
# You may opt to use, copy, modify, merge, publish, distribute and/or sell
# copies of the Software, and permit persons to whom the Software is
# furnished to do so, under the terms of the COPYING file.
#
# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
# KIND, either express or implied.
#
# SPDX-License-Identifier: curl
#
###########################################################################
# Find the c-ares library
#
# Input variables:
#
# - `CARES_INCLUDE_DIR`: The c-ares include directory.
# - `CARES_LIBRARY`: Path to `cares` library.
#
# Result variables:
#
# - `CARES_FOUND`: System has c-ares.
# - `CARES_INCLUDE_DIRS`: The c-ares include directories.
# - `CARES_LIBRARIES`: The c-ares library names.
# - `CARES_VERSION`: Version of c-ares.
if(CURL_USE_PKGCONFIG)
find_package(PkgConfig QUIET)
pkg_check_modules(PC_CARES "libcares")
endif()
find_path(CARES_INCLUDE_DIR NAMES "ares.h"
HINTS
${PC_CARES_INCLUDEDIR}
${PC_CARES_INCLUDE_DIRS}
)
find_library(CARES_LIBRARY NAMES ${CARES_NAMES} "cares"
HINTS
${PC_CARES_LIBDIR}
${PC_CARES_LIBRARY_DIRS}
)
if(PC_CARES_VERSION)
set(CARES_VERSION ${PC_CARES_VERSION})
elseif(CARES_INCLUDE_DIR AND EXISTS "${CARES_INCLUDE_DIR}/ares_version.h")
set(_version_regex1 "#[\t ]*define[\t ]+ARES_VERSION_MAJOR[\t ]+([0-9]+).*")
set(_version_regex2 "#[\t ]*define[\t ]+ARES_VERSION_MINOR[\t ]+([0-9]+).*")
set(_version_regex3 "#[\t ]*define[\t ]+ARES_VERSION_PATCH[\t ]+([0-9]+).*")
file(STRINGS "${CARES_INCLUDE_DIR}/ares_version.h" _version_str1 REGEX "${_version_regex1}")
file(STRINGS "${CARES_INCLUDE_DIR}/ares_version.h" _version_str2 REGEX "${_version_regex2}")
file(STRINGS "${CARES_INCLUDE_DIR}/ares_version.h" _version_str3 REGEX "${_version_regex3}")
string(REGEX REPLACE "${_version_regex1}" "\\1" _version_str1 "${_version_str1}")
string(REGEX REPLACE "${_version_regex2}" "\\1" _version_str2 "${_version_str2}")
string(REGEX REPLACE "${_version_regex3}" "\\1" _version_str3 "${_version_str3}")
set(CARES_VERSION "${_version_str1}.${_version_str2}.${_version_str3}")
unset(_version_regex1)
unset(_version_regex2)
unset(_version_regex3)
unset(_version_str1)
unset(_version_str2)
unset(_version_str3)
endif()
include(FindPackageHandleStandardArgs)
find_package_handle_standard_args(Cares
REQUIRED_VARS
CARES_INCLUDE_DIR
CARES_LIBRARY
VERSION_VAR
CARES_VERSION
)
if(CARES_FOUND)
set(CARES_INCLUDE_DIRS ${CARES_INCLUDE_DIR})
set(CARES_LIBRARIES ${CARES_LIBRARY})
endif()
mark_as_advanced(CARES_INCLUDE_DIR CARES_LIBRARY)