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import os 

import shutil 

import subprocess 

import sys 

 

# 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 == "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): 

# Run GCC's linker with the -t (aka --trace) option and examine the 

# library name it prints out. The GCC command will fail because we 

# haven't supplied a proper program with main(), but that does not 

# matter. 

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

 

c_compiler = shutil.which('gcc') 

if not c_compiler: 

c_compiler = shutil.which('cc') 

if not c_compiler: 

# No C compiler available, give up 

return None 

 

temp = tempfile.NamedTemporaryFile() 

try: 

args = [c_compiler, '-Wl,-t', '-o', temp.name, '-l' + name] 

 

env = dict(os.environ) 

env['LC_ALL'] = 'C' 

env['LANG'] = 'C' 

try: 

proc = subprocess.Popen(args, 

stdout=subprocess.PIPE, 

stderr=subprocess.STDOUT, 

env=env) 

except OSError: # E.g. bad executable 

return None 

with proc: 

trace = proc.stdout.read() 

finally: 

try: 

temp.close() 

except FileNotFoundError: 

# Raised if the file was already removed, which is the normal 

# behaviour of GCC if linking fails 

pass 

res = re.search(expr, trace) 

if not res: 

return None 

return os.fsdecode(res.group(0)) 

 

 

if sys.platform == "sunos5": 

# use /usr/ccs/bin/dump on solaris 

def _get_soname(f): 

if not f: 

return None 

 

try: 

proc = subprocess.Popen(("/usr/ccs/bin/dump", "-Lpv", f), 

stdout=subprocess.PIPE, 

stderr=subprocess.DEVNULL) 

except OSError: # E.g. command not found 

return None 

with proc: 

data = proc.stdout.read() 

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

if not res: 

return None 

return os.fsdecode(res.group(1)) 

else: 

def _get_soname(f): 

# assuming GNU binutils / ELF 

if not f: 

return None 

objdump = shutil.which('objdump') 

if not objdump: 

# objdump is not available, give up 

return None 

 

try: 

proc = subprocess.Popen((objdump, '-p', '-j', '.dynamic', f), 

stdout=subprocess.PIPE, 

stderr=subprocess.DEVNULL) 

except OSError: # E.g. bad executable 

return None 

with proc: 

dump = proc.stdout.read() 

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

if not res: 

return None 

return os.fsdecode(res.group(1)) 

 

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

 

def _num_version(libname): 

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

parts = libname.split(b".") 

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) 

expr = os.fsencode(expr) 

 

try: 

proc = subprocess.Popen(('/sbin/ldconfig', '-r'), 

stdout=subprocess.PIPE, 

stderr=subprocess.DEVNULL) 

except OSError: # E.g. command not found 

data = b'' 

else: 

with proc: 

data = proc.stdout.read() 

 

res = re.findall(expr, data) 

if not res: 

return _get_soname(_findLib_gcc(name)) 

res.sort(key=_num_version) 

return os.fsdecode(res[-1]) 

 

elif sys.platform == "sunos5": 

 

def _findLib_crle(name, is64): 

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

return None 

 

env = dict(os.environ) 

env['LC_ALL'] = 'C' 

 

if is64: 

args = ('/usr/bin/crle', '-64') 

else: 

args = ('/usr/bin/crle',) 

 

paths = None 

try: 

proc = subprocess.Popen(args, 

stdout=subprocess.PIPE, 

stderr=subprocess.DEVNULL, 

env=env) 

except OSError: # E.g. bad executable 

return None 

with proc: 

for line in proc.stdout: 

line = line.strip() 

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

paths = os.fsdecode(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 _findLib_ld(name): 

# See issue #9998 for why this is needed 

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

cmd = ['ld', '-t'] 

libpath = os.environ.get('LD_LIBRARY_PATH') 

if libpath: 

for d in libpath.split(':'): 

cmd.extend(['-L', d]) 

cmd.extend(['-o', os.devnull, '-l%s' % name]) 

result = None 

try: 

p = subprocess.Popen(cmd, stdout=subprocess.PIPE, 

stderr=subprocess.PIPE, 

universal_newlines=True) 

out, _ = p.communicate() 

res = re.search(expr, os.fsdecode(out)) 

if res: 

result = res.group(0) 

except Exception as e: 

pass # result will be None 

return result 

 

def find_library(name): 

# See issue #9998 

return _findSoname_ldconfig(name) or \ 

_get_soname(_findLib_gcc(name) or _findLib_ld(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()