FindPythonLibsNew.cmake revision 12391:ceeca8b41e4b 
1# - Find python libraries
2# This module finds the libraries corresponding to the Python interpeter
3# FindPythonInterp provides.
4# This code sets the following variables:
5#
6#  PYTHONLIBS_FOUND           - have the Python libs been found
7#  PYTHON_PREFIX              - path to the Python installation
8#  PYTHON_LIBRARIES           - path to the python library
9#  PYTHON_INCLUDE_DIRS        - path to where Python.h is found
10#  PYTHON_MODULE_EXTENSION    - lib extension, e.g. '.so' or '.pyd'
11#  PYTHON_MODULE_PREFIX       - lib name prefix: usually an empty string
12#  PYTHON_SITE_PACKAGES       - path to installation site-packages
13#  PYTHON_IS_DEBUG            - whether the Python interpreter is a debug build
14#
15# Thanks to talljimbo for the patch adding the 'LDVERSION' config
16# variable usage.
17
18#=============================================================================
19# Copyright 2001-2009 Kitware, Inc.
20# Copyright 2012 Continuum Analytics, Inc.
21#
22# All rights reserved.
23#
24# Redistribution and use in source and binary forms, with or without
25# modification, are permitted provided that the following conditions
26# are met:
27#
28# * Redistributions of source code must retain the above copyright
29# notice, this list of conditions and the following disclaimer.
30#
31# * Redistributions in binary form must reproduce the above copyright
32# notice, this list of conditions and the following disclaimer in the
33# documentation and/or other materials provided with the distribution.
34#
35# * Neither the names of Kitware, Inc., the Insight Software Consortium,
36# nor the names of their contributors may be used to endorse or promote
37# products derived from this software without specific prior written
38# permission.
39#
40# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
41# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
42# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
43# # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
44# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
45# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
46# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
47# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
48# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
49# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
50# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
51#=============================================================================
52
53# Checking for the extension makes sure that `LibsNew` was found and not just `Libs`.
54if(PYTHONLIBS_FOUND AND PYTHON_MODULE_EXTENSION)
55    return()
56endif()
57
58# Use the Python interpreter to find the libs.
59if(PythonLibsNew_FIND_REQUIRED)
60    find_package(PythonInterp ${PythonLibsNew_FIND_VERSION} REQUIRED)
61else()
62    find_package(PythonInterp ${PythonLibsNew_FIND_VERSION})
63endif()
64
65if(NOT PYTHONINTERP_FOUND)
66    set(PYTHONLIBS_FOUND FALSE)
67    return()
68endif()
69
70# According to http://stackoverflow.com/questions/646518/python-how-to-detect-debug-interpreter
71# testing whether sys has the gettotalrefcount function is a reliable, cross-platform
72# way to detect a CPython debug interpreter.
73#
74# The library suffix is from the config var LDVERSION sometimes, otherwise
75# VERSION. VERSION will typically be like "2.7" on unix, and "27" on windows.
76execute_process(COMMAND "${PYTHON_EXECUTABLE}" "-c"
77    "from distutils import sysconfig as s;import sys;import struct;
78print('.'.join(str(v) for v in sys.version_info));
79print(sys.prefix);
80print(s.get_python_inc(plat_specific=True));
81print(s.get_python_lib(plat_specific=True));
82print(s.get_config_var('SO'));
83print(hasattr(sys, 'gettotalrefcount')+0);
84print(struct.calcsize('@P'));
85print(s.get_config_var('LDVERSION') or s.get_config_var('VERSION'));
86print(s.get_config_var('LIBDIR') or '');
87print(s.get_config_var('MULTIARCH') or '');
88"
89    RESULT_VARIABLE _PYTHON_SUCCESS
90    OUTPUT_VARIABLE _PYTHON_VALUES
91    ERROR_VARIABLE _PYTHON_ERROR_VALUE)
92
93if(NOT _PYTHON_SUCCESS MATCHES 0)
94    if(PythonLibsNew_FIND_REQUIRED)
95        message(FATAL_ERROR
96            "Python config failure:\n${_PYTHON_ERROR_VALUE}")
97    endif()
98    set(PYTHONLIBS_FOUND FALSE)
99    return()
100endif()
101
102# Convert the process output into a list
103string(REGEX REPLACE ";" "\\\\;" _PYTHON_VALUES ${_PYTHON_VALUES})
104string(REGEX REPLACE "\n" ";" _PYTHON_VALUES ${_PYTHON_VALUES})
105list(GET _PYTHON_VALUES 0 _PYTHON_VERSION_LIST)
106list(GET _PYTHON_VALUES 1 PYTHON_PREFIX)
107list(GET _PYTHON_VALUES 2 PYTHON_INCLUDE_DIR)
108list(GET _PYTHON_VALUES 3 PYTHON_SITE_PACKAGES)
109list(GET _PYTHON_VALUES 4 PYTHON_MODULE_EXTENSION)
110list(GET _PYTHON_VALUES 5 PYTHON_IS_DEBUG)
111list(GET _PYTHON_VALUES 6 PYTHON_SIZEOF_VOID_P)
112list(GET _PYTHON_VALUES 7 PYTHON_LIBRARY_SUFFIX)
113list(GET _PYTHON_VALUES 8 PYTHON_LIBDIR)
114list(GET _PYTHON_VALUES 9 PYTHON_MULTIARCH)
115
116# Make sure the Python has the same pointer-size as the chosen compiler
117# Skip if CMAKE_SIZEOF_VOID_P is not defined
118if(CMAKE_SIZEOF_VOID_P AND (NOT "${PYTHON_SIZEOF_VOID_P}" STREQUAL "${CMAKE_SIZEOF_VOID_P}"))
119    if(PythonLibsNew_FIND_REQUIRED)
120        math(EXPR _PYTHON_BITS "${PYTHON_SIZEOF_VOID_P} * 8")
121        math(EXPR _CMAKE_BITS "${CMAKE_SIZEOF_VOID_P} * 8")
122        message(FATAL_ERROR
123            "Python config failure: Python is ${_PYTHON_BITS}-bit, "
124            "chosen compiler is  ${_CMAKE_BITS}-bit")
125    endif()
126    set(PYTHONLIBS_FOUND FALSE)
127    return()
128endif()
129
130# The built-in FindPython didn't always give the version numbers
131string(REGEX REPLACE "\\." ";" _PYTHON_VERSION_LIST ${_PYTHON_VERSION_LIST})
132list(GET _PYTHON_VERSION_LIST 0 PYTHON_VERSION_MAJOR)
133list(GET _PYTHON_VERSION_LIST 1 PYTHON_VERSION_MINOR)
134list(GET _PYTHON_VERSION_LIST 2 PYTHON_VERSION_PATCH)
135
136# Make sure all directory separators are '/'
137string(REGEX REPLACE "\\\\" "/" PYTHON_PREFIX ${PYTHON_PREFIX})
138string(REGEX REPLACE "\\\\" "/" PYTHON_INCLUDE_DIR ${PYTHON_INCLUDE_DIR})
139string(REGEX REPLACE "\\\\" "/" PYTHON_SITE_PACKAGES ${PYTHON_SITE_PACKAGES})
140
141if(CMAKE_HOST_WIN32)
142    set(PYTHON_LIBRARY
143        "${PYTHON_PREFIX}/libs/Python${PYTHON_LIBRARY_SUFFIX}.lib")
144
145    # when run in a venv, PYTHON_PREFIX points to it. But the libraries remain in the
146    # original python installation. They may be found relative to PYTHON_INCLUDE_DIR.
147    if(NOT EXISTS "${PYTHON_LIBRARY}")
148        get_filename_component(_PYTHON_ROOT ${PYTHON_INCLUDE_DIR} DIRECTORY)
149        set(PYTHON_LIBRARY
150            "${_PYTHON_ROOT}/libs/Python${PYTHON_LIBRARY_SUFFIX}.lib")
151    endif()
152
153    # raise an error if the python libs are still not found.
154    if(NOT EXISTS "${PYTHON_LIBRARY}")
155        message(FATAL_ERROR "Python libraries not found")
156    endif()
157
158else()
159    if(PYTHON_MULTIARCH)
160        set(_PYTHON_LIBS_SEARCH "${PYTHON_LIBDIR}/${PYTHON_MULTIARCH}" "${PYTHON_LIBDIR}")
161    else()
162        set(_PYTHON_LIBS_SEARCH "${PYTHON_LIBDIR}")
163    endif()
164    #message(STATUS "Searching for Python libs in ${_PYTHON_LIBS_SEARCH}")
165    # Probably this needs to be more involved. It would be nice if the config
166    # information the python interpreter itself gave us were more complete.
167    find_library(PYTHON_LIBRARY
168        NAMES "python${PYTHON_LIBRARY_SUFFIX}"
169        PATHS ${_PYTHON_LIBS_SEARCH}
170        NO_DEFAULT_PATH)
171
172    # If all else fails, just set the name/version and let the linker figure out the path.
173    if(NOT PYTHON_LIBRARY)
174        set(PYTHON_LIBRARY python${PYTHON_LIBRARY_SUFFIX})
175    endif()
176endif()
177
178MARK_AS_ADVANCED(
179  PYTHON_LIBRARY
180  PYTHON_INCLUDE_DIR
181)
182
183# We use PYTHON_INCLUDE_DIR, PYTHON_LIBRARY and PYTHON_DEBUG_LIBRARY for the
184# cache entries because they are meant to specify the location of a single
185# library. We now set the variables listed by the documentation for this
186# module.
187SET(PYTHON_INCLUDE_DIRS "${PYTHON_INCLUDE_DIR}")
188SET(PYTHON_LIBRARIES "${PYTHON_LIBRARY}")
189SET(PYTHON_DEBUG_LIBRARIES "${PYTHON_DEBUG_LIBRARY}")
190
191find_package_message(PYTHON
192    "Found PythonLibs: ${PYTHON_LIBRARY}"
193    "${PYTHON_EXECUTABLE}${PYTHON_VERSION}")
194
195set(PYTHONLIBS_FOUND TRUE)
196