Python code coverage for Lib/distutils/sysconfig.py

#	count	content
1	n/a	"""Provide access to Python's configuration information. The specific
2	n/a	configuration variables available depend heavily on the platform and
3	n/a	configuration. The values may be retrieved using
4	n/a	get_config_var(name), and the list of variables is available via
5	n/a	get_config_vars().keys(). Additional convenience functions are also
6	n/a	available.
7	n/a
8	n/a	Written by: Fred L. Drake, Jr.
9	n/a	Email: <fdrake@acm.org>
10	n/a	"""
11	n/a
12	n/a	import _imp
13	n/a	import os
14	n/a	import re
15	n/a	import sys
16	n/a
17	n/a	from .errors import DistutilsPlatformError
18	n/a
19	n/a	# These are needed in a couple of spots, so just compute them once.
20	n/a	PREFIX = os.path.normpath(sys.prefix)
21	n/a	EXEC_PREFIX = os.path.normpath(sys.exec_prefix)
22	n/a	BASE_PREFIX = os.path.normpath(sys.base_prefix)
23	n/a	BASE_EXEC_PREFIX = os.path.normpath(sys.base_exec_prefix)
24	n/a
25	n/a	# Path to the base directory of the project. On Windows the binary may
26	n/a	# live in project/PCBuild/win32 or project/PCBuild/amd64.
27	n/a	# set for cross builds
28	n/a	if "_PYTHON_PROJECT_BASE" in os.environ:
29	n/a	project_base = os.path.abspath(os.environ["_PYTHON_PROJECT_BASE"])
30	n/a	else:
31	n/a	project_base = os.path.dirname(os.path.abspath(sys.executable))
32	n/a	if (os.name == 'nt' and
33	n/a	project_base.lower().endswith(('\\pcbuild\\win32', '\\pcbuild\\amd64'))):
34	n/a	project_base = os.path.dirname(os.path.dirname(project_base))
35	n/a
36	n/a	# python_build: (Boolean) if true, we're either building Python or
37	n/a	# building an extension with an un-installed Python, so we use
38	n/a	# different (hard-wired) directories.
39	n/a	# Setup.local is available for Makefile builds including VPATH builds,
40	n/a	# Setup.dist is available on Windows
41	n/a	def _is_python_source_dir(d):
42	n/a	for fn in ("Setup.dist", "Setup.local"):
43	n/a	if os.path.isfile(os.path.join(d, "Modules", fn)):
44	n/a	return True
45	n/a	return False
46	n/a	_sys_home = getattr(sys, '_home', None)
47	n/a	if (_sys_home and os.name == 'nt' and
48	n/a	_sys_home.lower().endswith(('\\pcbuild\\win32', '\\pcbuild\\amd64'))):
49	n/a	_sys_home = os.path.dirname(os.path.dirname(_sys_home))
50	n/a	def _python_build():
51	n/a	if _sys_home:
52	n/a	return _is_python_source_dir(_sys_home)
53	n/a	return _is_python_source_dir(project_base)
54	n/a	python_build = _python_build()
55	n/a
56	n/a	# Calculate the build qualifier flags if they are defined. Adding the flags
57	n/a	# to the include and lib directories only makes sense for an installation, not
58	n/a	# an in-source build.
59	n/a	build_flags = ''
60	n/a	try:
61	n/a	if not python_build:
62	n/a	build_flags = sys.abiflags
63	n/a	except AttributeError:
64	n/a	# It's not a configure-based build, so the sys module doesn't have
65	n/a	# this attribute, which is fine.
66	n/a	pass
67	n/a
68	n/a	def get_python_version():
69	n/a	"""Return a string containing the major and minor Python version,
70	n/a	leaving off the patchlevel. Sample return values could be '1.5'
71	n/a	or '2.2'.
72	n/a	"""
73	n/a	return '%d.%d' % sys.version_info[:2]
74	n/a
75	n/a
76	n/a	def get_python_inc(plat_specific=0, prefix=None):
77	n/a	"""Return the directory containing installed Python header files.
78	n/a
79	n/a	If 'plat_specific' is false (the default), this is the path to the
80	n/a	non-platform-specific header files, i.e. Python.h and so on;
81	n/a	otherwise, this is the path to platform-specific header files
82	n/a	(namely pyconfig.h).
83	n/a
84	n/a	If 'prefix' is supplied, use it instead of sys.base_prefix or
85	n/a	sys.base_exec_prefix -- i.e., ignore 'plat_specific'.
86	n/a	"""
87	n/a	if prefix is None:
88	n/a	prefix = plat_specific and BASE_EXEC_PREFIX or BASE_PREFIX
89	n/a	if os.name == "posix":
90	n/a	if python_build:
91	n/a	# Assume the executable is in the build directory. The
92	n/a	# pyconfig.h file should be in the same directory. Since
93	n/a	# the build directory may not be the source directory, we
94	n/a	# must use "srcdir" from the makefile to find the "Include"
95	n/a	# directory.
96	n/a	base = _sys_home or project_base
97	n/a	if plat_specific:
98	n/a	return base
99	n/a	if _sys_home:
100	n/a	incdir = os.path.join(_sys_home, get_config_var('AST_H_DIR'))
101	n/a	else:
102	n/a	incdir = os.path.join(get_config_var('srcdir'), 'Include')
103	n/a	return os.path.normpath(incdir)
104	n/a	python_dir = 'python' + get_python_version() + build_flags
105	n/a	return os.path.join(prefix, "include", python_dir)
106	n/a	elif os.name == "nt":
107	n/a	return os.path.join(prefix, "include")
108	n/a	else:
109	n/a	raise DistutilsPlatformError(
110	n/a	"I don't know where Python installs its C header files "
111	n/a	"on platform '%s'" % os.name)
112	n/a
113	n/a
114	n/a	def get_python_lib(plat_specific=0, standard_lib=0, prefix=None):
115	n/a	"""Return the directory containing the Python library (standard or
116	n/a	site additions).
117	n/a
118	n/a	If 'plat_specific' is true, return the directory containing
119	n/a	platform-specific modules, i.e. any module from a non-pure-Python
120	n/a	module distribution; otherwise, return the platform-shared library
121	n/a	directory. If 'standard_lib' is true, return the directory
122	n/a	containing standard Python library modules; otherwise, return the
123	n/a	directory for site-specific modules.
124	n/a
125	n/a	If 'prefix' is supplied, use it instead of sys.base_prefix or
126	n/a	sys.base_exec_prefix -- i.e., ignore 'plat_specific'.
127	n/a	"""
128	n/a	if prefix is None:
129	n/a	if standard_lib:
130	n/a	prefix = plat_specific and BASE_EXEC_PREFIX or BASE_PREFIX
131	n/a	else:
132	n/a	prefix = plat_specific and EXEC_PREFIX or PREFIX
133	n/a
134	n/a	if os.name == "posix":
135	n/a	libpython = os.path.join(prefix,
136	n/a	"lib", "python" + get_python_version())
137	n/a	if standard_lib:
138	n/a	return libpython
139	n/a	else:
140	n/a	return os.path.join(libpython, "site-packages")
141	n/a	elif os.name == "nt":
142	n/a	if standard_lib:
143	n/a	return os.path.join(prefix, "Lib")
144	n/a	else:
145	n/a	return os.path.join(prefix, "Lib", "site-packages")
146	n/a	else:
147	n/a	raise DistutilsPlatformError(
148	n/a	"I don't know where Python installs its library "
149	n/a	"on platform '%s'" % os.name)
150	n/a
151	n/a
152	n/a
153	n/a	def customize_compiler(compiler):
154	n/a	"""Do any platform-specific customization of a CCompiler instance.
155	n/a
156	n/a	Mainly needed on Unix, so we can plug in the information that
157	n/a	varies across Unices and is stored in Python's Makefile.
158	n/a	"""
159	n/a	if compiler.compiler_type == "unix":
160	n/a	if sys.platform == "darwin":
161	n/a	# Perform first-time customization of compiler-related
162	n/a	# config vars on OS X now that we know we need a compiler.
163	n/a	# This is primarily to support Pythons from binary
164	n/a	# installers. The kind and paths to build tools on
165	n/a	# the user system may vary significantly from the system
166	n/a	# that Python itself was built on. Also the user OS
167	n/a	# version and build tools may not support the same set
168	n/a	# of CPU architectures for universal builds.
169	n/a	global _config_vars
170	n/a	# Use get_config_var() to ensure _config_vars is initialized.
171	n/a	if not get_config_var('CUSTOMIZED_OSX_COMPILER'):
172	n/a	import _osx_support
173	n/a	_osx_support.customize_compiler(_config_vars)
174	n/a	_config_vars['CUSTOMIZED_OSX_COMPILER'] = 'True'
175	n/a
176	n/a	(cc, cxx, opt, cflags, ccshared, ldshared, shlib_suffix, ar, ar_flags) = \
177	n/a	get_config_vars('CC', 'CXX', 'OPT', 'CFLAGS',
178	n/a	'CCSHARED', 'LDSHARED', 'SHLIB_SUFFIX', 'AR', 'ARFLAGS')
179	n/a
180	n/a	if 'CC' in os.environ:
181	n/a	newcc = os.environ['CC']
182	n/a	if (sys.platform == 'darwin'
183	n/a	and 'LDSHARED' not in os.environ
184	n/a	and ldshared.startswith(cc)):
185	n/a	# On OS X, if CC is overridden, use that as the default
186	n/a	# command for LDSHARED as well
187	n/a	ldshared = newcc + ldshared[len(cc):]
188	n/a	cc = newcc
189	n/a	if 'CXX' in os.environ:
190	n/a	cxx = os.environ['CXX']
191	n/a	if 'LDSHARED' in os.environ:
192	n/a	ldshared = os.environ['LDSHARED']
193	n/a	if 'CPP' in os.environ:
194	n/a	cpp = os.environ['CPP']
195	n/a	else:
196	n/a	cpp = cc + " -E" # not always
197	n/a	if 'LDFLAGS' in os.environ:
198	n/a	ldshared = ldshared + ' ' + os.environ['LDFLAGS']
199	n/a	if 'CFLAGS' in os.environ:
200	n/a	cflags = opt + ' ' + os.environ['CFLAGS']
201	n/a	ldshared = ldshared + ' ' + os.environ['CFLAGS']
202	n/a	if 'CPPFLAGS' in os.environ:
203	n/a	cpp = cpp + ' ' + os.environ['CPPFLAGS']
204	n/a	cflags = cflags + ' ' + os.environ['CPPFLAGS']
205	n/a	ldshared = ldshared + ' ' + os.environ['CPPFLAGS']
206	n/a	if 'AR' in os.environ:
207	n/a	ar = os.environ['AR']
208	n/a	if 'ARFLAGS' in os.environ:
209	n/a	archiver = ar + ' ' + os.environ['ARFLAGS']
210	n/a	else:
211	n/a	archiver = ar + ' ' + ar_flags
212	n/a
213	n/a	cc_cmd = cc + ' ' + cflags
214	n/a	compiler.set_executables(
215	n/a	preprocessor=cpp,
216	n/a	compiler=cc_cmd,
217	n/a	compiler_so=cc_cmd + ' ' + ccshared,
218	n/a	compiler_cxx=cxx,
219	n/a	linker_so=ldshared,
220	n/a	linker_exe=cc,
221	n/a	archiver=archiver)
222	n/a
223	n/a	compiler.shared_lib_extension = shlib_suffix
224	n/a
225	n/a
226	n/a	def get_config_h_filename():
227	n/a	"""Return full pathname of installed pyconfig.h file."""
228	n/a	if python_build:
229	n/a	if os.name == "nt":
230	n/a	inc_dir = os.path.join(_sys_home or project_base, "PC")
231	n/a	else:
232	n/a	inc_dir = _sys_home or project_base
233	n/a	else:
234	n/a	inc_dir = get_python_inc(plat_specific=1)
235	n/a
236	n/a	return os.path.join(inc_dir, 'pyconfig.h')
237	n/a
238	n/a
239	n/a	def get_makefile_filename():
240	n/a	"""Return full pathname of installed Makefile from the Python build."""
241	n/a	if python_build:
242	n/a	return os.path.join(_sys_home or project_base, "Makefile")
243	n/a	lib_dir = get_python_lib(plat_specific=0, standard_lib=1)
244	n/a	config_file = 'config-{}{}'.format(get_python_version(), build_flags)
245	n/a	if hasattr(sys.implementation, '_multiarch'):
246	n/a	config_file += '-%s' % sys.implementation._multiarch
247	n/a	return os.path.join(lib_dir, config_file, 'Makefile')
248	n/a
249	n/a
250	n/a	def parse_config_h(fp, g=None):
251	n/a	"""Parse a config.h-style file.
252	n/a
253	n/a	A dictionary containing name/value pairs is returned. If an
254	n/a	optional dictionary is passed in as the second argument, it is
255	n/a	used instead of a new dictionary.
256	n/a	"""
257	n/a	if g is None:
258	n/a	g = {}
259	n/a	define_rx = re.compile("#define ([A-Z][A-Za-z0-9_]+) (.*)\n")
260	n/a	undef_rx = re.compile("/[] #undef ([A-Z][A-Za-z0-9_]+) []/\n")
261	n/a	#
262	n/a	while True:
263	n/a	line = fp.readline()
264	n/a	if not line:
265	n/a	break
266	n/a	m = define_rx.match(line)
267	n/a	if m:
268	n/a	n, v = m.group(1, 2)
269	n/a	try: v = int(v)
270	n/a	except ValueError: pass
271	n/a	g[n] = v
272	n/a	else:
273	n/a	m = undef_rx.match(line)
274	n/a	if m:
275	n/a	g[m.group(1)] = 0
276	n/a	return g
277	n/a
278	n/a
279	n/a	# Regexes needed for parsing Makefile (and similar syntaxes,
280	n/a	# like old-style Setup files).
281	n/a	_variable_rx = re.compile(r"([a-zA-Z][a-zA-Z0-9_]+)\s=\s(.*)")
282	n/a	_findvar1_rx = re.compile(r"\$$([A-Za-z][A-Za-z0-9_]*)$")
283	n/a	_findvar2_rx = re.compile(r"\${([A-Za-z][A-Za-z0-9_]*)}")
284	n/a
285	n/a	def parse_makefile(fn, g=None):
286	n/a	"""Parse a Makefile-style file.
287	n/a
288	n/a	A dictionary containing name/value pairs is returned. If an
289	n/a	optional dictionary is passed in as the second argument, it is
290	n/a	used instead of a new dictionary.
291	n/a	"""
292	n/a	from distutils.text_file import TextFile
293	n/a	fp = TextFile(fn, strip_comments=1, skip_blanks=1, join_lines=1, errors="surrogateescape")
294	n/a
295	n/a	if g is None:
296	n/a	g = {}
297	n/a	done = {}
298	n/a	notdone = {}
299	n/a
300	n/a	while True:
301	n/a	line = fp.readline()
302	n/a	if line is None: # eof
303	n/a	break
304	n/a	m = _variable_rx.match(line)
305	n/a	if m:
306	n/a	n, v = m.group(1, 2)
307	n/a	v = v.strip()
308	n/a	# `$$' is a literal `$' in make
309	n/a	tmpv = v.replace('$$', '')
310	n/a
311	n/a	if "$" in tmpv:
312	n/a	notdone[n] = v
313	n/a	else:
314	n/a	try:
315	n/a	v = int(v)
316	n/a	except ValueError:
317	n/a	# insert literal `$'
318	n/a	done[n] = v.replace('$$', '$')
319	n/a	else:
320	n/a	done[n] = v
321	n/a
322	n/a	# Variables with a 'PY_' prefix in the makefile. These need to
323	n/a	# be made available without that prefix through sysconfig.
324	n/a	# Special care is needed to ensure that variable expansion works, even
325	n/a	# if the expansion uses the name without a prefix.
326	n/a	renamed_variables = ('CFLAGS', 'LDFLAGS', 'CPPFLAGS')
327	n/a
328	n/a	# do variable interpolation here
329	n/a	while notdone:
330	n/a	for name in list(notdone):
331	n/a	value = notdone[name]
332	n/a	m = _findvar1_rx.search(value) or _findvar2_rx.search(value)
333	n/a	if m:
334	n/a	n = m.group(1)
335	n/a	found = True
336	n/a	if n in done:
337	n/a	item = str(done[n])
338	n/a	elif n in notdone:
339	n/a	# get it on a subsequent round
340	n/a	found = False
341	n/a	elif n in os.environ:
342	n/a	# do it like make: fall back to environment
343	n/a	item = os.environ[n]
344	n/a
345	n/a	elif n in renamed_variables:
346	n/a	if name.startswith('PY_') and name[3:] in renamed_variables:
347	n/a	item = ""
348	n/a
349	n/a	elif 'PY_' + n in notdone:
350	n/a	found = False
351	n/a
352	n/a	else:
353	n/a	item = str(done['PY_' + n])
354	n/a	else:
355	n/a	done[n] = item = ""
356	n/a	if found:
357	n/a	after = value[m.end():]
358	n/a	value = value[:m.start()] + item + after
359	n/a	if "$" in after:
360	n/a	notdone[name] = value
361	n/a	else:
362	n/a	try: value = int(value)
363	n/a	except ValueError:
364	n/a	done[name] = value.strip()
365	n/a	else:
366	n/a	done[name] = value
367	n/a	del notdone[name]
368	n/a
369	n/a	if name.startswith('PY_') \
370	n/a	and name[3:] in renamed_variables:
371	n/a
372	n/a	name = name[3:]
373	n/a	if name not in done:
374	n/a	done[name] = value
375	n/a	else:
376	n/a	# bogus variable reference; just drop it since we can't deal
377	n/a	del notdone[name]
378	n/a
379	n/a	fp.close()
380	n/a
381	n/a	# strip spurious spaces
382	n/a	for k, v in done.items():
383	n/a	if isinstance(v, str):
384	n/a	done[k] = v.strip()
385	n/a
386	n/a	# save the results in the global dictionary
387	n/a	g.update(done)
388	n/a	return g
389	n/a
390	n/a
391	n/a	def expand_makefile_vars(s, vars):
392	n/a	"""Expand Makefile-style variables -- "${foo}" or "$(foo)" -- in
393	n/a	'string' according to 'vars' (a dictionary mapping variable names to
394	n/a	values). Variables not present in 'vars' are silently expanded to the
395	n/a	empty string. The variable values in 'vars' should not contain further
396	n/a	variable expansions; if 'vars' is the output of 'parse_makefile()',
397	n/a	you're fine. Returns a variable-expanded version of 's'.
398	n/a	"""
399	n/a
400	n/a	# This algorithm does multiple expansion, so if vars['foo'] contains
401	n/a	# "${bar}", it will expand ${foo} to ${bar}, and then expand
402	n/a	# ${bar}... and so forth. This is fine as long as 'vars' comes from
403	n/a	# 'parse_makefile()', which takes care of such expansions eagerly,
404	n/a	# according to make's variable expansion semantics.
405	n/a
406	n/a	while True:
407	n/a	m = _findvar1_rx.search(s) or _findvar2_rx.search(s)
408	n/a	if m:
409	n/a	(beg, end) = m.span()
410	n/a	s = s[0:beg] + vars.get(m.group(1)) + s[end:]
411	n/a	else:
412	n/a	break
413	n/a	return s
414	n/a
415	n/a
416	n/a	_config_vars = None
417	n/a
418	n/a	def _init_posix():
419	n/a	"""Initialize the module as appropriate for POSIX systems."""
420	n/a	# _sysconfigdata is generated at build time, see the sysconfig module
421	n/a	name = os.environ.get('_PYTHON_SYSCONFIGDATA_NAME',
422	n/a	'_sysconfigdata_{abi}_{platform}_{multiarch}'.format(
423	n/a	abi=sys.abiflags,
424	n/a	platform=sys.platform,
425	n/a	multiarch=getattr(sys.implementation, '_multiarch', ''),
426	n/a	))
427	n/a	_temp = __import__(name, globals(), locals(), ['build_time_vars'], 0)
428	n/a	build_time_vars = _temp.build_time_vars
429	n/a	global _config_vars
430	n/a	_config_vars = {}
431	n/a	_config_vars.update(build_time_vars)
432	n/a
433	n/a
434	n/a	def _init_nt():
435	n/a	"""Initialize the module as appropriate for NT"""
436	n/a	g = {}
437	n/a	# set basic install directories
438	n/a	g['LIBDEST'] = get_python_lib(plat_specific=0, standard_lib=1)
439	n/a	g['BINLIBDEST'] = get_python_lib(plat_specific=1, standard_lib=1)
440	n/a
441	n/a	# XXX hmmm.. a normal install puts include files here
442	n/a	g['INCLUDEPY'] = get_python_inc(plat_specific=0)
443	n/a
444	n/a	g['EXT_SUFFIX'] = _imp.extension_suffixes()[0]
445	n/a	g['EXE'] = ".exe"
446	n/a	g['VERSION'] = get_python_version().replace(".", "")
447	n/a	g['BINDIR'] = os.path.dirname(os.path.abspath(sys.executable))
448	n/a
449	n/a	global _config_vars
450	n/a	_config_vars = g
451	n/a
452	n/a
453	n/a	def get_config_vars(*args):
454	n/a	"""With no arguments, return a dictionary of all configuration
455	n/a	variables relevant for the current platform. Generally this includes
456	n/a	everything needed to build extensions and install both pure modules and
457	n/a	extensions. On Unix, this means every variable defined in Python's
458	n/a	installed Makefile; on Windows it's a much smaller set.
459	n/a
460	n/a	With arguments, return a list of values that result from looking up
461	n/a	each argument in the configuration variable dictionary.
462	n/a	"""
463	n/a	global _config_vars
464	n/a	if _config_vars is None:
465	n/a	func = globals().get("_init_" + os.name)
466	n/a	if func:
467	n/a	func()
468	n/a	else:
469	n/a	_config_vars = {}
470	n/a
471	n/a	# Normalized versions of prefix and exec_prefix are handy to have;
472	n/a	# in fact, these are the standard versions used most places in the
473	n/a	# Distutils.
474	n/a	_config_vars['prefix'] = PREFIX
475	n/a	_config_vars['exec_prefix'] = EXEC_PREFIX
476	n/a
477	n/a	# For backward compatibility, see issue19555
478	n/a	SO = _config_vars.get('EXT_SUFFIX')
479	n/a	if SO is not None:
480	n/a	_config_vars['SO'] = SO
481	n/a
482	n/a	# Always convert srcdir to an absolute path
483	n/a	srcdir = _config_vars.get('srcdir', project_base)
484	n/a	if os.name == 'posix':
485	n/a	if python_build:
486	n/a	# If srcdir is a relative path (typically '.' or '..')
487	n/a	# then it should be interpreted relative to the directory
488	n/a	# containing Makefile.
489	n/a	base = os.path.dirname(get_makefile_filename())
490	n/a	srcdir = os.path.join(base, srcdir)
491	n/a	else:
492	n/a	# srcdir is not meaningful since the installation is
493	n/a	# spread about the filesystem. We choose the
494	n/a	# directory containing the Makefile since we know it
495	n/a	# exists.
496	n/a	srcdir = os.path.dirname(get_makefile_filename())
497	n/a	_config_vars['srcdir'] = os.path.abspath(os.path.normpath(srcdir))
498	n/a
499	n/a	# Convert srcdir into an absolute path if it appears necessary.
500	n/a	# Normally it is relative to the build directory. However, during
501	n/a	# testing, for example, we might be running a non-installed python
502	n/a	# from a different directory.
503	n/a	if python_build and os.name == "posix":
504	n/a	base = project_base
505	n/a	if (not os.path.isabs(_config_vars['srcdir']) and
506	n/a	base != os.getcwd()):
507	n/a	# srcdir is relative and we are not in the same directory
508	n/a	# as the executable. Assume executable is in the build
509	n/a	# directory and make srcdir absolute.
510	n/a	srcdir = os.path.join(base, _config_vars['srcdir'])
511	n/a	_config_vars['srcdir'] = os.path.normpath(srcdir)
512	n/a
513	n/a	# OS X platforms require special customization to handle
514	n/a	# multi-architecture, multi-os-version installers
515	n/a	if sys.platform == 'darwin':
516	n/a	import _osx_support
517	n/a	_osx_support.customize_config_vars(_config_vars)
518	n/a
519	n/a	if args:
520	n/a	vals = []
521	n/a	for name in args:
522	n/a	vals.append(_config_vars.get(name))
523	n/a	return vals
524	n/a	else:
525	n/a	return _config_vars
526	n/a
527	n/a	def get_config_var(name):
528	n/a	"""Return the value of a single variable using the dictionary
529	n/a	returned by 'get_config_vars()'. Equivalent to
530	n/a	get_config_vars().get(name)
531	n/a	"""
532	n/a	if name == 'SO':
533	n/a	import warnings
534	n/a	warnings.warn('SO is deprecated, use EXT_SUFFIX', DeprecationWarning, 2)
535	n/a	return get_config_vars().get(name)