import sys, os

import contextlib

import subprocess

# find_library(name) returns the pathname of a library, or None.

if os.name == "nt":

def _get_build_version():

"""Return the version of MSVC that was used to build Python.

For Python 2.3 and up, the version number is included in

sys.version. For earlier versions, assume the compiler is MSVC 6.

"""

# This function was copied from Lib/distutils/msvccompiler.py

prefix = "MSC v."

i = sys.version.find(prefix)

if i == -1:

return 6

i = i + len(prefix)

s, rest = sys.version[i:].split(" ", 1)

majorVersion = int(s[:-2]) - 6

if majorVersion >= 13:

majorVersion += 1

minorVersion = int(s[2:3]) / 10.0

# I don't think paths are affected by minor version in version 6

if majorVersion == 6:

minorVersion = 0

if majorVersion >= 6:

return majorVersion + minorVersion

# else we don't know what version of the compiler this is

return None

def find_msvcrt():

"""Return the name of the VC runtime dll"""

version = _get_build_version()

if version is None:

# better be safe than sorry

return None

if version <= 6:

clibname = 'msvcrt'

elif version <= 13:

clibname = 'msvcr%d' % (version * 10)

else:

# CRT is no longer directly loadable. See issue23606 for the

# discussion about alternative approaches.

return None

# If python was built with in debug mode

import importlib.machinery

if '_d.pyd' in importlib.machinery.EXTENSION_SUFFIXES:

clibname += 'd'

return clibname+'.dll'

def find_library(name):

if name in ('c', 'm'):

return find_msvcrt()

# See MSDN for the REAL search order.

for directory in os.environ['PATH'].split(os.pathsep):

fname = os.path.join(directory, name)

if os.path.isfile(fname):

return fname

if fname.lower().endswith(".dll"):

continue

fname = fname + ".dll"

if os.path.isfile(fname):

return fname

return None

if os.name == "ce":

# search path according to MSDN:

# - absolute path specified by filename

# - The .exe launch directory

# - the Windows directory

# - ROM dll files (where are they?)

# - OEM specified search path: HKLM\Loader\SystemPath

def find_library(name):

return name

if os.name == "posix" and sys.platform == "darwin":

from ctypes.macholib.dyld import dyld_find as _dyld_find

def find_library(name):

possible = ['lib%s.dylib' % name,

'%s.dylib' % name,

'%s.framework/%s' % (name, name)]

for name in possible:

try:

return _dyld_find(name)

except ValueError:

continue

return None

elif os.name == "posix":

# Andreas Degert's find functions, using gcc, /sbin/ldconfig, objdump

import re, tempfile

def _findLib_gcc(name):

expr = r'[^\(\)\s]*lib%s\.[^\(\)\s]*' % re.escape(name)

fdout, ccout = tempfile.mkstemp()

os.close(fdout)

cmd = 'if type gcc >/dev/null 2>&1; then CC=gcc; elif type cc >/dev/null 2>&1; then CC=cc;else exit 10; fi;' \

'LANG=C LC_ALL=C $CC -Wl,-t -o ' + ccout + ' 2>&1 -l' + name

try:

f = os.popen(cmd)

try:

trace = f.read()

finally:

rv = f.close()

finally:

try:

os.unlink(ccout)

except FileNotFoundError:

pass

if rv == 10:

raise OSError('gcc or cc command not found')

res = re.search(expr, trace)

if not res:

return None

return res.group(0)

if sys.platform == "sunos5":

# use /usr/ccs/bin/dump on solaris

def _get_soname(f):

if not f:

return None

cmd = "/usr/ccs/bin/dump -Lpv 2>/dev/null " + f

with contextlib.closing(os.popen(cmd)) as f:

data = f.read()

res = re.search(r'\[.*\]\sSONAME\s+([^\s]+)', data)

if not res:

return None

return res.group(1)

else:

def _get_soname(f):

# assuming GNU binutils / ELF

if not f:

return None

cmd = 'if ! type objdump >/dev/null 2>&1; then exit 10; fi;' \

"objdump -p -j .dynamic 2>/dev/null " + f

f = os.popen(cmd)

try:

dump = f.read()

finally:

rv = f.close()

if rv == 10:

raise OSError('objdump command not found')

res = re.search(r'\sSONAME\s+([^\s]+)', dump)

if not res:

return None

return res.group(1)

if sys.platform.startswith(("freebsd", "openbsd", "dragonfly")):

def _num_version(libname):

# "libxyz.so.MAJOR.MINOR" => [ MAJOR, MINOR ]

parts = libname.split(".")

nums = []

try:

while parts:

nums.insert(0, int(parts.pop()))

except ValueError:

pass

return nums or [ sys.maxsize ]

def find_library(name):

ename = re.escape(name)

expr = r':-l%s\.\S+ => \S*/(lib%s\.\S+)' % (ename, ename)

with contextlib.closing(os.popen('/sbin/ldconfig -r 2>/dev/null')) as f:

data = f.read()

res = re.findall(expr, data)

if not res:

return _get_soname(_findLib_gcc(name))

res.sort(key=_num_version)

return res[-1]

elif sys.platform == "sunos5":

def _findLib_crle(name, is64):

if not os.path.exists('/usr/bin/crle'):

return None

if is64:

cmd = 'env LC_ALL=C /usr/bin/crle -64 2>/dev/null'

else:

cmd = 'env LC_ALL=C /usr/bin/crle 2>/dev/null'

paths = None

with contextlib.closing(os.popen(cmd)) as f:

for line in f.readlines():

line = line.strip()

if line.startswith('Default Library Path (ELF):'):

paths = line.split()[4]

if not paths:

return None

for dir in paths.split(":"):

libfile = os.path.join(dir, "lib%s.so" % name)

if os.path.exists(libfile):

return libfile

return None

def find_library(name, is64 = False):

return _get_soname(_findLib_crle(name, is64) or _findLib_gcc(name))

else:

def _findSoname_ldconfig(name):

import struct

if struct.calcsize('l') == 4:

machine = os.uname().machine + '-32'

else:

machine = os.uname().machine + '-64'

mach_map = {

'x86_64-64': 'libc6,x86-64',

'ppc64-64': 'libc6,64bit',

'sparc64-64': 'libc6,64bit',

's390x-64': 'libc6,64bit',

'ia64-64': 'libc6,IA-64',

}

abi_type = mach_map.get(machine, 'libc6')

# XXX assuming GLIBC's ldconfig (with option -p)

regex = r'\s+(lib%s\.[^\s]+)\s+\(%s'

regex = os.fsencode(regex % (re.escape(name), abi_type))

try:

with subprocess.Popen(['/sbin/ldconfig', '-p'],

stdin=subprocess.DEVNULL,

stderr=subprocess.DEVNULL,

stdout=subprocess.PIPE,

env={'LC_ALL': 'C', 'LANG': 'C'}) as p:

res = re.search(regex, p.stdout.read())

if res:

return os.fsdecode(res.group(1))

except OSError:

pass

def find_library(name):

return _findSoname_ldconfig(name) or _get_soname(_findLib_gcc(name))

################################################################

# test code

def test():

from ctypes import cdll

if os.name == "nt":

print(cdll.msvcrt)

print(cdll.load("msvcrt"))

print(find_library("msvcrt"))

if os.name == "posix":

# find and load_version

print(find_library("m"))

print(find_library("c"))

print(find_library("bz2"))

# getattr

## print cdll.m

## print cdll.bz2

# load

if sys.platform == "darwin":

print(cdll.LoadLibrary("libm.dylib"))

print(cdll.LoadLibrary("libcrypto.dylib"))

print(cdll.LoadLibrary("libSystem.dylib"))

print(cdll.LoadLibrary("System.framework/System"))

else:

print(cdll.LoadLibrary("libm.so"))

print(cdll.LoadLibrary("libcrypt.so"))

print(find_library("crypt"))

if __name__ == "__main__":

test()