1#!/usr/bin/env python
2# encoding: utf-8
3# Thomas Nagy, 2007-2015 (ita)
4# Gustavo Carneiro (gjc), 2007
5
6"""
7Support for Python, detect the headers and libraries and provide
8*use* variables to link C/C++ programs against them::
9
10	def options(opt):
11		opt.load('compiler_c python')
12	def configure(conf):
13		conf.load('compiler_c python')
14		conf.check_python_version((2,4,2))
15		conf.check_python_headers()
16	def build(bld):
17		bld.program(features='pyembed', source='a.c', target='myprog')
18		bld.shlib(features='pyext', source='b.c', target='mylib')
19"""
20
21import os, sys
22from waflib import Errors, Logs, Node, Options, Task, Utils
23from waflib.TaskGen import extension, before_method, after_method, feature
24from waflib.Configure import conf
25
26FRAG = '''
27#include <Python.h>
28#ifdef __cplusplus
29extern "C" {
30#endif
31	void Py_Initialize(void);
32	void Py_Finalize(void);
33#ifdef __cplusplus
34}
35#endif
36int main(int argc, char **argv)
37{
38   (void)argc; (void)argv;
39   Py_Initialize();
40   Py_Finalize();
41   return 0;
42}
43'''
44"""
45Piece of C/C++ code used in :py:func:`waflib.Tools.python.check_python_headers`
46"""
47
48INST = '''
49import sys, py_compile
50py_compile.compile(sys.argv[1], sys.argv[2], sys.argv[3], True)
51'''
52"""
53Piece of Python code used in :py:class:`waflib.Tools.python.pyo` and :py:class:`waflib.Tools.python.pyc` for byte-compiling python files
54"""
55
56DISTUTILS_IMP = ['from distutils.sysconfig import get_config_var, get_python_lib']
57
58@before_method('process_source')
59@feature('py')
60def feature_py(self):
61	"""
62	Create tasks to byte-compile .py files and install them, if requested
63	"""
64	self.install_path = getattr(self, 'install_path', '${PYTHONDIR}')
65	install_from = getattr(self, 'install_from', None)
66	if install_from and not isinstance(install_from, Node.Node):
67		install_from = self.path.find_dir(install_from)
68	self.install_from = install_from
69
70	ver = self.env.PYTHON_VERSION
71	if not ver:
72		self.bld.fatal('Installing python files requires PYTHON_VERSION, try conf.check_python_version')
73
74	if int(ver.replace('.', '')) > 31:
75		self.install_32 = True
76
77@extension('.py')
78def process_py(self, node):
79	"""
80	Add signature of .py file, so it will be byte-compiled when necessary
81	"""
82	assert(hasattr(self, 'install_path')), 'add features="py"'
83
84	# where to install the python file
85	if self.install_path:
86		if self.install_from:
87			self.add_install_files(install_to=self.install_path, install_from=node, cwd=self.install_from, relative_trick=True)
88		else:
89			self.add_install_files(install_to=self.install_path, install_from=node, relative_trick=True)
90
91	lst = []
92	if self.env.PYC:
93		lst.append('pyc')
94	if self.env.PYO:
95		lst.append('pyo')
96
97	if self.install_path:
98		if self.install_from:
99			pyd = Utils.subst_vars("%s/%s" % (self.install_path, node.path_from(self.install_from)), self.env)
100		else:
101			pyd = Utils.subst_vars("%s/%s" % (self.install_path, node.path_from(self.path)), self.env)
102	else:
103		pyd = node.abspath()
104
105	for ext in lst:
106		if self.env.PYTAG and not self.env.NOPYCACHE:
107			# __pycache__ installation for python 3.2 - PEP 3147
108			name = node.name[:-3]
109			pyobj = node.parent.get_bld().make_node('__pycache__').make_node("%s.%s.%s" % (name, self.env.PYTAG, ext))
110			pyobj.parent.mkdir()
111		else:
112			pyobj = node.change_ext(".%s" % ext)
113
114		tsk = self.create_task(ext, node, pyobj)
115		tsk.pyd = pyd
116
117		if self.install_path:
118			self.add_install_files(install_to=os.path.dirname(pyd), install_from=pyobj, cwd=node.parent.get_bld(), relative_trick=True)
119
120class pyc(Task.Task):
121	"""
122	Byte-compiling python files
123	"""
124	color = 'PINK'
125	def __str__(self):
126		node = self.outputs[0]
127		return node.path_from(node.ctx.launch_node())
128	def run(self):
129		cmd = [Utils.subst_vars('${PYTHON}', self.env), '-c', INST, self.inputs[0].abspath(), self.outputs[0].abspath(), self.pyd]
130		ret = self.generator.bld.exec_command(cmd)
131		return ret
132
133class pyo(Task.Task):
134	"""
135	Byte-compiling python files
136	"""
137	color = 'PINK'
138	def __str__(self):
139		node = self.outputs[0]
140		return node.path_from(node.ctx.launch_node())
141	def run(self):
142		cmd = [Utils.subst_vars('${PYTHON}', self.env), Utils.subst_vars('${PYFLAGS_OPT}', self.env), '-c', INST, self.inputs[0].abspath(), self.outputs[0].abspath(), self.pyd]
143		ret = self.generator.bld.exec_command(cmd)
144		return ret
145
146@feature('pyext')
147@before_method('propagate_uselib_vars', 'apply_link')
148@after_method('apply_bundle')
149def init_pyext(self):
150	"""
151	Change the values of *cshlib_PATTERN* and *cxxshlib_PATTERN* to remove the
152	*lib* prefix from library names.
153	"""
154	self.uselib = self.to_list(getattr(self, 'uselib', []))
155	if not 'PYEXT' in self.uselib:
156		self.uselib.append('PYEXT')
157	# override shlib_PATTERN set by the osx module
158	self.env.cshlib_PATTERN = self.env.cxxshlib_PATTERN = self.env.macbundle_PATTERN = self.env.pyext_PATTERN
159	self.env.fcshlib_PATTERN = self.env.dshlib_PATTERN = self.env.pyext_PATTERN
160
161	try:
162		if not self.install_path:
163			return
164	except AttributeError:
165		self.install_path = '${PYTHONARCHDIR}'
166
167@feature('pyext')
168@before_method('apply_link', 'apply_bundle')
169def set_bundle(self):
170	"""Mac-specific pyext extension that enables bundles from c_osx.py"""
171	if Utils.unversioned_sys_platform() == 'darwin':
172		self.mac_bundle = True
173
174@before_method('propagate_uselib_vars')
175@feature('pyembed')
176def init_pyembed(self):
177	"""
178	Add the PYEMBED variable.
179	"""
180	self.uselib = self.to_list(getattr(self, 'uselib', []))
181	if not 'PYEMBED' in self.uselib:
182		self.uselib.append('PYEMBED')
183
184@conf
185def get_python_variables(self, variables, imports=None):
186	"""
187	Spawn a new python process to dump configuration variables
188
189	:param variables: variables to print
190	:type variables: list of string
191	:param imports: one import by element
192	:type imports: list of string
193	:return: the variable values
194	:rtype: list of string
195	"""
196	if not imports:
197		try:
198			imports = self.python_imports
199		except AttributeError:
200			imports = DISTUTILS_IMP
201
202	program = list(imports) # copy
203	program.append('')
204	for v in variables:
205		program.append("print(repr(%s))" % v)
206	os_env = dict(os.environ)
207	try:
208		del os_env['MACOSX_DEPLOYMENT_TARGET'] # see comments in the OSX tool
209	except KeyError:
210		pass
211
212	try:
213		out = self.cmd_and_log(self.env.PYTHON + ['-c', '\n'.join(program)], env=os_env)
214	except Errors.WafError:
215		self.fatal('The distutils module is unusable: install "python-devel"?')
216	self.to_log(out)
217	return_values = []
218	for s in out.splitlines():
219		s = s.strip()
220		if not s:
221			continue
222		if s == 'None':
223			return_values.append(None)
224		elif (s[0] == "'" and s[-1] == "'") or (s[0] == '"' and s[-1] == '"'):
225			return_values.append(eval(s))
226		elif s[0].isdigit():
227			return_values.append(int(s))
228		else: break
229	return return_values
230
231@conf
232def test_pyembed(self, mode, msg='Testing pyembed configuration'):
233	self.check(header_name='Python.h', define_name='HAVE_PYEMBED', msg=msg,
234		fragment=FRAG, errmsg='Could not build a python embedded interpreter',
235		features='%s %sprogram pyembed' % (mode, mode))
236
237@conf
238def test_pyext(self, mode, msg='Testing pyext configuration'):
239	self.check(header_name='Python.h', define_name='HAVE_PYEXT', msg=msg,
240		fragment=FRAG, errmsg='Could not build python extensions',
241		features='%s %sshlib pyext' % (mode, mode))
242
243@conf
244def python_cross_compile(self, features='pyembed pyext'):
245	"""
246	For cross-compilation purposes, it is possible to bypass the normal detection and set the flags that you want:
247	PYTHON_VERSION='3.4' PYTAG='cpython34' pyext_PATTERN="%s.so" PYTHON_LDFLAGS='-lpthread -ldl' waf configure
248
249	The following variables are used:
250	PYTHON_VERSION    required
251	PYTAG             required
252	PYTHON_LDFLAGS    required
253	pyext_PATTERN     required
254	PYTHON_PYEXT_LDFLAGS
255	PYTHON_PYEMBED_LDFLAGS
256	"""
257	features = Utils.to_list(features)
258	if not ('PYTHON_LDFLAGS' in self.environ or 'PYTHON_PYEXT_LDFLAGS' in self.environ or 'PYTHON_PYEMBED_LDFLAGS' in self.environ):
259		return False
260
261	for x in 'PYTHON_VERSION PYTAG pyext_PATTERN'.split():
262		if not x in self.environ:
263			self.fatal('Please set %s in the os environment' % x)
264		else:
265			self.env[x] = self.environ[x]
266
267	xx = self.env.CXX_NAME and 'cxx' or 'c'
268	if 'pyext' in features:
269		flags = self.environ.get('PYTHON_PYEXT_LDFLAGS', self.environ.get('PYTHON_LDFLAGS'))
270		if flags is None:
271			self.fatal('No flags provided through PYTHON_PYEXT_LDFLAGS as required')
272		else:
273			self.parse_flags(flags, 'PYEXT')
274		self.test_pyext(xx)
275	if 'pyembed' in features:
276		flags = self.environ.get('PYTHON_PYEMBED_LDFLAGS', self.environ.get('PYTHON_LDFLAGS'))
277		if flags is None:
278			self.fatal('No flags provided through PYTHON_PYEMBED_LDFLAGS as required')
279		else:
280			self.parse_flags(flags, 'PYEMBED')
281		self.test_pyembed(xx)
282	return True
283
284@conf
285def check_python_headers(conf, features='pyembed pyext'):
286	"""
287	Check for headers and libraries necessary to extend or embed python by using the module *distutils*.
288	On success the environment variables xxx_PYEXT and xxx_PYEMBED are added:
289
290	* PYEXT: for compiling python extensions
291	* PYEMBED: for embedding a python interpreter
292	"""
293	features = Utils.to_list(features)
294	assert ('pyembed' in features) or ('pyext' in features), "check_python_headers features must include 'pyembed' and/or 'pyext'"
295	env = conf.env
296	if not env.CC_NAME and not env.CXX_NAME:
297		conf.fatal('load a compiler first (gcc, g++, ..)')
298
299	# bypass all the code below for cross-compilation
300	if conf.python_cross_compile(features):
301		return
302
303	if not env.PYTHON_VERSION:
304		conf.check_python_version()
305
306	pybin = env.PYTHON
307	if not pybin:
308		conf.fatal('Could not find the python executable')
309
310	# so we actually do all this for compatibility reasons and for obtaining pyext_PATTERN below
311	v = 'prefix SO LDFLAGS LIBDIR LIBPL INCLUDEPY Py_ENABLE_SHARED MACOSX_DEPLOYMENT_TARGET LDSHARED CFLAGS LDVERSION'.split()
312	try:
313		lst = conf.get_python_variables(["get_config_var('%s') or ''" % x for x in v])
314	except RuntimeError:
315		conf.fatal("Python development headers not found (-v for details).")
316
317	vals = ['%s = %r' % (x, y) for (x, y) in zip(v, lst)]
318	conf.to_log("Configuration returned from %r:\n%s\n" % (pybin, '\n'.join(vals)))
319
320	dct = dict(zip(v, lst))
321	x = 'MACOSX_DEPLOYMENT_TARGET'
322	if dct[x]:
323		env[x] = conf.environ[x] = dct[x]
324	env.pyext_PATTERN = '%s' + dct['SO'] # not a mistake
325
326
327	# Try to get pythonX.Y-config
328	num = '.'.join(env.PYTHON_VERSION.split('.')[:2])
329	conf.find_program([''.join(pybin) + '-config', 'python%s-config' % num, 'python-config-%s' % num, 'python%sm-config' % num], var='PYTHON_CONFIG', msg="python-config", mandatory=False)
330
331	if env.PYTHON_CONFIG:
332		# check python-config output only once
333		if conf.env.HAVE_PYTHON_H:
334			return
335
336		# python2.6-config requires 3 runs
337		all_flags = [['--cflags', '--libs', '--ldflags']]
338		if sys.hexversion < 0x2070000:
339			all_flags = [[k] for k in all_flags[0]]
340
341		xx = env.CXX_NAME and 'cxx' or 'c'
342
343		if 'pyembed' in features:
344			for flags in all_flags:
345				# Python 3.8 has different flags for pyembed, needs --embed
346				embedflags = flags + ['--embed']
347				try:
348					conf.check_cfg(msg='Asking python-config for pyembed %r flags' % ' '.join(embedflags), path=env.PYTHON_CONFIG, package='', uselib_store='PYEMBED', args=embedflags)
349				except conf.errors.ConfigurationError:
350					# However Python < 3.8 doesn't accept --embed, so we need a fallback
351					conf.check_cfg(msg='Asking python-config for pyembed %r flags' % ' '.join(flags), path=env.PYTHON_CONFIG, package='', uselib_store='PYEMBED', args=flags)
352
353			try:
354				conf.test_pyembed(xx)
355			except conf.errors.ConfigurationError:
356				# python bug 7352
357				if dct['Py_ENABLE_SHARED'] and dct['LIBDIR']:
358					env.append_unique('LIBPATH_PYEMBED', [dct['LIBDIR']])
359					conf.test_pyembed(xx)
360				else:
361					raise
362
363		if 'pyext' in features:
364			for flags in all_flags:
365				conf.check_cfg(msg='Asking python-config for pyext %r flags' % ' '.join(flags), path=env.PYTHON_CONFIG, package='', uselib_store='PYEXT', args=flags)
366
367			try:
368				conf.test_pyext(xx)
369			except conf.errors.ConfigurationError:
370				# python bug 7352
371				if dct['Py_ENABLE_SHARED'] and dct['LIBDIR']:
372					env.append_unique('LIBPATH_PYEXT', [dct['LIBDIR']])
373					conf.test_pyext(xx)
374				else:
375					raise
376
377		conf.define('HAVE_PYTHON_H', 1)
378		return
379
380	# No python-config, do something else on windows systems
381	all_flags = dct['LDFLAGS'] + ' ' + dct['CFLAGS']
382	conf.parse_flags(all_flags, 'PYEMBED')
383
384	all_flags = dct['LDFLAGS'] + ' ' + dct['LDSHARED'] + ' ' + dct['CFLAGS']
385	conf.parse_flags(all_flags, 'PYEXT')
386
387	result = None
388	if not dct["LDVERSION"]:
389		dct["LDVERSION"] = env.PYTHON_VERSION
390
391	# further simplification will be complicated
392	for name in ('python' + dct['LDVERSION'], 'python' + env.PYTHON_VERSION + 'm', 'python' + env.PYTHON_VERSION.replace('.', '')):
393
394		# LIBPATH_PYEMBED is already set; see if it works.
395		if not result and env.LIBPATH_PYEMBED:
396			path = env.LIBPATH_PYEMBED
397			conf.to_log("\n\n# Trying default LIBPATH_PYEMBED: %r\n" % path)
398			result = conf.check(lib=name, uselib='PYEMBED', libpath=path, mandatory=False, msg='Checking for library %s in LIBPATH_PYEMBED' % name)
399
400		if not result and dct['LIBDIR']:
401			path = [dct['LIBDIR']]
402			conf.to_log("\n\n# try again with -L$python_LIBDIR: %r\n" % path)
403			result = conf.check(lib=name, uselib='PYEMBED', libpath=path, mandatory=False, msg='Checking for library %s in LIBDIR' % name)
404
405		if not result and dct['LIBPL']:
406			path = [dct['LIBPL']]
407			conf.to_log("\n\n# try again with -L$python_LIBPL (some systems don't install the python library in $prefix/lib)\n")
408			result = conf.check(lib=name, uselib='PYEMBED', libpath=path, mandatory=False, msg='Checking for library %s in python_LIBPL' % name)
409
410		if not result:
411			path = [os.path.join(dct['prefix'], "libs")]
412			conf.to_log("\n\n# try again with -L$prefix/libs, and pythonXY name rather than pythonX.Y (win32)\n")
413			result = conf.check(lib=name, uselib='PYEMBED', libpath=path, mandatory=False, msg='Checking for library %s in $prefix/libs' % name)
414
415		if result:
416			break # do not forget to set LIBPATH_PYEMBED
417
418	if result:
419		env.LIBPATH_PYEMBED = path
420		env.append_value('LIB_PYEMBED', [name])
421	else:
422		conf.to_log("\n\n### LIB NOT FOUND\n")
423
424	# under certain conditions, python extensions must link to
425	# python libraries, not just python embedding programs.
426	if Utils.is_win32 or dct['Py_ENABLE_SHARED']:
427		env.LIBPATH_PYEXT = env.LIBPATH_PYEMBED
428		env.LIB_PYEXT = env.LIB_PYEMBED
429
430	conf.to_log("Include path for Python extensions (found via distutils module): %r\n" % (dct['INCLUDEPY'],))
431	env.INCLUDES_PYEXT = [dct['INCLUDEPY']]
432	env.INCLUDES_PYEMBED = [dct['INCLUDEPY']]
433
434	# Code using the Python API needs to be compiled with -fno-strict-aliasing
435	if env.CC_NAME == 'gcc':
436		env.append_value('CFLAGS_PYEMBED', ['-fno-strict-aliasing'])
437		env.append_value('CFLAGS_PYEXT', ['-fno-strict-aliasing'])
438	if env.CXX_NAME == 'gcc':
439		env.append_value('CXXFLAGS_PYEMBED', ['-fno-strict-aliasing'])
440		env.append_value('CXXFLAGS_PYEXT', ['-fno-strict-aliasing'])
441
442	if env.CC_NAME == "msvc":
443		from distutils.msvccompiler import MSVCCompiler
444		dist_compiler = MSVCCompiler()
445		dist_compiler.initialize()
446		env.append_value('CFLAGS_PYEXT', dist_compiler.compile_options)
447		env.append_value('CXXFLAGS_PYEXT', dist_compiler.compile_options)
448		env.append_value('LINKFLAGS_PYEXT', dist_compiler.ldflags_shared)
449
450	# See if it compiles
451	conf.check(header_name='Python.h', define_name='HAVE_PYTHON_H', uselib='PYEMBED', fragment=FRAG, errmsg='Distutils not installed? Broken python installation? Get python-config now!')
452
453@conf
454def check_python_version(conf, minver=None):
455	"""
456	Check if the python interpreter is found matching a given minimum version.
457	minver should be a tuple, eg. to check for python >= 2.4.2 pass (2,4,2) as minver.
458
459	If successful, PYTHON_VERSION is defined as 'MAJOR.MINOR' (eg. '2.4')
460	of the actual python version found, and PYTHONDIR and PYTHONARCHDIR
461	are defined, pointing to the site-packages directories appropriate for
462	this python version, where modules/packages/extensions should be
463	installed.
464
465	:param minver: minimum version
466	:type minver: tuple of int
467	"""
468	assert minver is None or isinstance(minver, tuple)
469	pybin = conf.env.PYTHON
470	if not pybin:
471		conf.fatal('could not find the python executable')
472
473	# Get python version string
474	cmd = pybin + ['-c', 'import sys\nfor x in sys.version_info: print(str(x))']
475	Logs.debug('python: Running python command %r', cmd)
476	lines = conf.cmd_and_log(cmd).split()
477	assert len(lines) == 5, "found %r lines, expected 5: %r" % (len(lines), lines)
478	pyver_tuple = (int(lines[0]), int(lines[1]), int(lines[2]), lines[3], int(lines[4]))
479
480	# Compare python version with the minimum required
481	result = (minver is None) or (pyver_tuple >= minver)
482
483	if result:
484		# define useful environment variables
485		pyver = '.'.join([str(x) for x in pyver_tuple[:2]])
486		conf.env.PYTHON_VERSION = pyver
487
488		if 'PYTHONDIR' in conf.env:
489			# Check if --pythondir was specified
490			pydir = conf.env.PYTHONDIR
491		elif 'PYTHONDIR' in conf.environ:
492			# Check environment for PYTHONDIR
493			pydir = conf.environ['PYTHONDIR']
494		else:
495			# Finally, try to guess
496			if Utils.is_win32:
497				(python_LIBDEST, pydir) = conf.get_python_variables(
498					  ["get_config_var('LIBDEST') or ''",
499					   "get_python_lib(standard_lib=0) or ''"])
500			else:
501				python_LIBDEST = None
502				(pydir,) = conf.get_python_variables( ["get_python_lib(standard_lib=0, prefix=%r) or ''" % conf.env.PREFIX])
503			if python_LIBDEST is None:
504				if conf.env.LIBDIR:
505					python_LIBDEST = os.path.join(conf.env.LIBDIR, 'python' + pyver)
506				else:
507					python_LIBDEST = os.path.join(conf.env.PREFIX, 'lib', 'python' + pyver)
508
509		if 'PYTHONARCHDIR' in conf.env:
510			# Check if --pythonarchdir was specified
511			pyarchdir = conf.env.PYTHONARCHDIR
512		elif 'PYTHONARCHDIR' in conf.environ:
513			# Check environment for PYTHONDIR
514			pyarchdir = conf.environ['PYTHONARCHDIR']
515		else:
516			# Finally, try to guess
517			(pyarchdir, ) = conf.get_python_variables( ["get_python_lib(plat_specific=1, standard_lib=0, prefix=%r) or ''" % conf.env.PREFIX])
518			if not pyarchdir:
519				pyarchdir = pydir
520
521		if hasattr(conf, 'define'): # conf.define is added by the C tool, so may not exist
522			conf.define('PYTHONDIR', pydir)
523			conf.define('PYTHONARCHDIR', pyarchdir)
524
525		conf.env.PYTHONDIR = pydir
526		conf.env.PYTHONARCHDIR = pyarchdir
527
528	# Feedback
529	pyver_full = '.'.join(map(str, pyver_tuple[:3]))
530	if minver is None:
531		conf.msg('Checking for python version', pyver_full)
532	else:
533		minver_str = '.'.join(map(str, minver))
534		conf.msg('Checking for python version >= %s' % (minver_str,), pyver_full, color=result and 'GREEN' or 'YELLOW')
535
536	if not result:
537		conf.fatal('The python version is too old, expecting %r' % (minver,))
538
539PYTHON_MODULE_TEMPLATE = '''
540import %s as current_module
541version = getattr(current_module, '__version__', None)
542if version is not None:
543	print(str(version))
544else:
545	print('unknown version')
546'''
547
548@conf
549def check_python_module(conf, module_name, condition=''):
550	"""
551	Check if the selected python interpreter can import the given python module::
552
553		def configure(conf):
554			conf.check_python_module('pygccxml')
555			conf.check_python_module('re', condition="ver > num(2, 0, 4) and ver <= num(3, 0, 0)")
556
557	:param module_name: module
558	:type module_name: string
559	"""
560	msg = "Checking for python module %r" % module_name
561	if condition:
562		msg = '%s (%s)' % (msg, condition)
563	conf.start_msg(msg)
564	try:
565		ret = conf.cmd_and_log(conf.env.PYTHON + ['-c', PYTHON_MODULE_TEMPLATE % module_name])
566	except Errors.WafError:
567		conf.end_msg(False)
568		conf.fatal('Could not find the python module %r' % module_name)
569
570	ret = ret.strip()
571	if condition:
572		conf.end_msg(ret)
573		if ret == 'unknown version':
574			conf.fatal('Could not check the %s version' % module_name)
575
576		from distutils.version import LooseVersion
577		def num(*k):
578			if isinstance(k[0], int):
579				return LooseVersion('.'.join([str(x) for x in k]))
580			else:
581				return LooseVersion(k[0])
582		d = {'num': num, 'ver': LooseVersion(ret)}
583		ev = eval(condition, {}, d)
584		if not ev:
585			conf.fatal('The %s version does not satisfy the requirements' % module_name)
586	else:
587		if ret == 'unknown version':
588			conf.end_msg(True)
589		else:
590			conf.end_msg(ret)
591
592def configure(conf):
593	"""
594	Detect the python interpreter
595	"""
596	v = conf.env
597	if getattr(Options.options, 'pythondir', None):
598		v.PYTHONDIR = Options.options.pythondir
599	if getattr(Options.options, 'pythonarchdir', None):
600		v.PYTHONARCHDIR = Options.options.pythonarchdir
601	if getattr(Options.options, 'nopycache', None):
602		v.NOPYCACHE=Options.options.nopycache
603
604	if not v.PYTHON:
605		v.PYTHON = [getattr(Options.options, 'python', None) or sys.executable]
606	v.PYTHON = Utils.to_list(v.PYTHON)
607	conf.find_program('python', var='PYTHON')
608
609	v.PYFLAGS = ''
610	v.PYFLAGS_OPT = '-O'
611
612	v.PYC = getattr(Options.options, 'pyc', 1)
613	v.PYO = getattr(Options.options, 'pyo', 1)
614
615	try:
616		v.PYTAG = conf.cmd_and_log(conf.env.PYTHON + ['-c', "import imp;print(imp.get_tag())"]).strip()
617	except Errors.WafError:
618		pass
619
620def options(opt):
621	"""
622	Add python-specific options
623	"""
624	pyopt=opt.add_option_group("Python Options")
625	pyopt.add_option('--nopyc', dest = 'pyc', action='store_false', default=1,
626					 help = 'Do not install bytecode compiled .pyc files (configuration) [Default:install]')
627	pyopt.add_option('--nopyo', dest='pyo', action='store_false', default=1,
628					 help='Do not install optimised compiled .pyo files (configuration) [Default:install]')
629	pyopt.add_option('--nopycache',dest='nopycache', action='store_true',
630					 help='Do not use __pycache__ directory to install objects [Default:auto]')
631	pyopt.add_option('--python', dest="python",
632					 help='python binary to be used [Default: %s]' % sys.executable)
633	pyopt.add_option('--pythondir', dest='pythondir',
634					 help='Installation path for python modules (py, platform-independent .py and .pyc files)')
635	pyopt.add_option('--pythonarchdir', dest='pythonarchdir',
636					 help='Installation path for python extension (pyext, platform-dependent .so or .dylib files)')
637
638