ctypes: loading .so file on Linux

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  • Paddy
    #1

    ctypes: loading .so file on Linux

    Hi,
    I am am falling at the first hurdle when trying to access a library
    using ctypes.

    I have a file libucdb.so which the file command says is shared object,
    but I cannot get it to load:

    Any help would be appreciated:

    dmccarthy: file /opt/questasim_6.4/questasim/linux/libucdb.a /opt/
    questasim_=
    6.4/questasim/linux/libucdb.so
    /opt/questasim_6.4/questasim/linux/libucdb.a: current ar archive
    /opt/questasim_6.4/questasim/linux/libucdb.so: ELF 32-bit LSB shared
    object,=
    Intel 80386, version 1 (SYSV), not stripped
    dmccarthy: python
    ActivePython 2.5.1.1 (ActiveState Software Inc.) based on
    Python 2.5.1 (r251:54863, May 2 2007, 08:46:07)
    [GCC 3.3.4 (pre 3.3.5 20040809)] on linux2
    Type "help", "copyright" , "credits" or "license" for more information.
    >>cdll.LoadLibr ary("libc.so.6" )
    Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    NameError: name 'cdll' is not defined
    >>from ctypes import *
    >>^[[A^[[A
    ^e "<stdin>", line 1
    SyntaxError: invalid syntax
    >>cdll.LoadLibr ary("libc.so.6" )
    <CDLL 'libc.so.6', handle 2a958a2900 at 2a95dda490>
    >>cdll.LoadLibr ary("libucdb.so ")
    Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "/software/unix-soft/linux/ActivePython-2.5.1.1-linux-x86_64/
    lib/pyth=
    on2.5/ctypes/__init__.py", line 423, in LoadLibrary
    return self._dlltype(n ame)
    File "/software/unix-soft/linux/ActivePython-2.5.1.1-linux-x86_64/
    lib/pyth=
    on2.5/ctypes/__init__.py", line 340, in __init__
    self._handle =3D _dlopen(self._n ame, mode)
    OSError: libucdb.so: cannot open shared object file: No such file or
    directo=
    ry
    >>cdll.LoadLibr ary("libc.so.6" )
    <CDLL 'libc.so.6', handle 2a958a2900 at 2a95df3ad0>
    >>libc =3D CDLL("libc.so.6 ")
    >>libc
    <CDLL 'libc.so.6', handle 2a958a2900 at 2a95dda490>
    >>libc =3D CDLL("libucdb.s o")
    Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "/software/unix-soft/linux/ActivePython-2.5.1.1-linux-x86_64/
    lib/pyth=
    on2.5/ctypes/__init__.py", line 340, in __init__
    self._handle =3D _dlopen(self._n ame, mode)
    OSError: libucdb.so: cannot open shared object file: No such file or
    directo=
    ry
    >>libc =3D CDLL("/opt/questasim_6.4/questasim/linux/libucdb.so")
    Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "/software/unix-soft/linux/ActivePython-2.5.1.1-linux-x86_64/
    lib/pyth=
    on2.5/ctypes/__init__.py", line 340, in __init__
    self._handle =3D _dlopen(self._n ame, mode)
    OSError: /opt/questasim_6.4/questasim/linux/libucdb.so: cannot open
    shared o=
    bject file: No such file or directory
    >>^[[A
    File "<stdin>", line 1
    ^
    SyntaxError: invalid syntax
    >>>
    - Paddy.
    Tags: None
    • Paddy
      #2
      Re: ctypes: loading .so file on Linux

      On Aug 23, 2:33 pm, Paddy <paddy3...@goog lemail.comwrote :
      Hi,
      I am am falling at the first hurdle when trying to access a library
      using ctypes.
      >
      I have a file libucdb.so which the file command says is shared object,
      but I cannot get it to load:
      >
      Any help would be appreciated:
      >
      dmccarthy: file /opt/questasim_6.4/questasim/linux/libucdb.a /opt/
      questasim_=
      6.4/questasim/linux/libucdb.so
      /opt/questasim_6.4/questasim/linux/libucdb.a:  current ar archive
      /opt/questasim_6.4/questasim/linux/libucdb.so: ELF 32-bit LSB shared
      object,=
       Intel 80386, version 1 (SYSV), not stripped
      dmccarthy: python
      ActivePython 2.5.1.1 (ActiveState Software Inc.) based on
      Python 2.5.1 (r251:54863, May  2 2007, 08:46:07)
      [GCC 3.3.4 (pre 3.3.5 20040809)] on linux2
      Type "help", "copyright" , "credits" or "license" for more information.>>> cdll.LoadLibrar y("libc.so.6" )
      >
      Traceback (most recent call last):
        File "<stdin>", line 1, in <module>
      NameError: name 'cdll' is not defined>>from ctypes import *
      >^[[A^[[A
      >
          ^e "<stdin>", line 1
      SyntaxError: invalid syntax>>cdll.Lo adLibrary("libc .so.6")
      >
      <CDLL 'libc.so.6', handle 2a958a2900 at 2a95dda490>>>cd ll.LoadLibrary( "libucdb.so ")
      >
      Traceback (most recent call last):
        File "<stdin>", line 1, in <module>
        File "/software/unix-soft/linux/ActivePython-2.5.1.1-linux-x86_64/
      lib/pyth=
      on2.5/ctypes/__init__.py", line 423, in LoadLibrary
          return self._dlltype(n ame)
        File "/software/unix-soft/linux/ActivePython-2.5.1.1-linux-x86_64/
      lib/pyth=
      on2.5/ctypes/__init__.py", line 340, in __init__
          self._handle =3D _dlopen(self._n ame, mode)
      OSError: libucdb.so: cannot open shared object file: No such file or
      directo=
      ry>>cdll.LoadLi brary("libc.so. 6")
      >
      <CDLL 'libc.so.6', handle 2a958a2900 at 2a95df3ad0>>>li bc =3D CDLL("libc.so.6 ")
      >libc
      >
      <CDLL 'libc.so.6', handle 2a958a2900 at 2a95dda490>>>li bc =3D CDLL("libucdb.s o")
      >
      Traceback (most recent call last):
        File "<stdin>", line 1, in <module>
        File "/software/unix-soft/linux/ActivePython-2.5.1.1-linux-x86_64/
      lib/pyth=
      on2.5/ctypes/__init__.py", line 340, in __init__
          self._handle =3D _dlopen(self._n ame, mode)
      OSError: libucdb.so: cannot open shared object file: No such file or
      directo=
      ry>>libc =3D CDLL("/opt/questasim_6.4/questasim/linux/libucdb.so")
      >
      Traceback (most recent call last):
        File "<stdin>", line 1, in <module>
        File "/software/unix-soft/linux/ActivePython-2.5.1.1-linux-x86_64/
      lib/pyth=
      on2.5/ctypes/__init__.py", line 340, in __init__
          self._handle =3D _dlopen(self._n ame, mode)
      OSError: /opt/questasim_6.4/questasim/linux/libucdb.so: cannot open
      shared o=
      bject file: No such file or directory>>^[[A
      >
        File "<stdin>", line 1
          ^
      SyntaxError: invalid syntax
      >
      >
      >
      - Paddy.
      Any help would be appreciated.

      Thanks.

        Comment

        • castironpi
          #3
          Re: ctypes: loading .so file on Linux

          On Aug 27, 12:03 am, Paddy <paddy3...@goog lemail.comwrote :
          On Aug 23, 2:33 pm, Paddy <paddy3...@goog lemail.comwrote :
          Hi,
          I am am falling at the first hurdle when trying to access a library
          using ctypes.
          >
          I have a file libucdb.so which the file command says is shared object,
          but I cannot get it to load:
          >
          Any help would be appreciated:
          >
          dmccarthy: file /opt/questasim_6.4/questasim/linux/libucdb.a /opt/
          questasim_=
          6.4/questasim/linux/libucdb.so
          /opt/questasim_6.4/questasim/linux/libucdb.a:  current ar archive
          /opt/questasim_6.4/questasim/linux/libucdb.so: ELF 32-bit LSB shared
          object,=
           Intel 80386, version 1 (SYSV), not stripped
          dmccarthy: python
          ActivePython 2.5.1.1 (ActiveState Software Inc.) based on
          Python 2.5.1 (r251:54863, May  2 2007, 08:46:07)
          [GCC 3.3.4 (pre 3.3.5 20040809)] on linux2
          Type "help", "copyright" , "credits" or "license" for more information.>>c dll.LoadLibrary ("libc.so.6" )
          >
          Traceback (most recent call last):
            File "<stdin>", line 1, in <module>
          NameError: name 'cdll' is not defined>>from ctypes import *
          >>^[[A^[[A
          >
              ^e "<stdin>", line 1
          SyntaxError: invalid syntax>>cdll.Lo adLibrary("libc .so.6")
          >
          <CDLL 'libc.so.6', handle 2a958a2900 at 2a95dda490>>>cd ll.LoadLibrary( "libucdb.so ")
          >
          Traceback (most recent call last):
            File "<stdin>", line 1, in <module>
            File "/software/unix-soft/linux/ActivePython-2.5.1.1-linux-x86_64/
          lib/pyth=
          on2.5/ctypes/__init__.py", line 423, in LoadLibrary
              return self._dlltype(n ame)
            File "/software/unix-soft/linux/ActivePython-2.5.1.1-linux-x86_64/
          lib/pyth=
          on2.5/ctypes/__init__.py", line 340, in __init__
              self._handle =3D _dlopen(self._n ame, mode)
          OSError: libucdb.so: cannot open shared object file: No such file or
          directo=
          ry>>cdll.LoadLi brary("libc.so. 6")
          >
          <CDLL 'libc.so.6', handle 2a958a2900 at 2a95df3ad0>>>li bc =3D CDLL("libc.so.6 ")
          >>libc
          >
          <CDLL 'libc.so.6', handle 2a958a2900 at 2a95dda490>>>li bc =3D CDLL("libucdb.s o")
          >
          Traceback (most recent call last):
            File "<stdin>", line 1, in <module>
            File "/software/unix-soft/linux/ActivePython-2.5.1.1-linux-x86_64/
          lib/pyth=
          on2.5/ctypes/__init__.py", line 340, in __init__
              self._handle =3D _dlopen(self._n ame, mode)
          OSError: libucdb.so: cannot open shared object file: No such file or
          directo=
          ry>>libc =3D CDLL("/opt/questasim_6.4/questasim/linux/libucdb.so")
          Try 'open( "libucdb.so ", "rb" )' to see if you're looking in the right
          place.

            Comment

            • Uwe Schmitt
              #4
              Re: ctypes: loading .so file on Linux

              On 27 Aug., 07:03, Paddy <paddy3...@goog lemail.comwrote :
              On Aug 23, 2:33 pm, Paddy <paddy3...@goog lemail.comwrote :
              >
              >
              >
              Hi,
              I am am falling at the first hurdle when trying to access a library
              using ctypes.
              >
              I have a file libucdb.so which the file command says is shared object,
              but I cannot get it to load:
              >
              Any help would be appreciated:
              >
              dmccarthy: file /opt/questasim_6.4/questasim/linux/libucdb.a /opt/
              questasim_=
              6.4/questasim/linux/libucdb.so
              /opt/questasim_6.4/questasim/linux/libucdb.a:  current ar archive
              /opt/questasim_6.4/questasim/linux/libucdb.so: ELF 32-bit LSB shared
              object,=
               Intel 80386, version 1 (SYSV), not stripped
              dmccarthy: python
              ActivePython 2.5.1.1 (ActiveState Software Inc.) based on
              Python 2.5.1 (r251:54863, May  2 2007, 08:46:07)
              [GCC 3.3.4 (pre 3.3.5 20040809)] on linux2
              Type "help", "copyright" , "credits" or "license" for more information.>>c dll.LoadLibrary ("libc.so.6" )
              >
              Traceback (most recent call last):
                File "<stdin>", line 1, in <module>
              NameError: name 'cdll' is not defined>>from ctypes import *
              >>^[[A^[[A
              >
                  ^e "<stdin>", line 1
              SyntaxError: invalid syntax>>cdll.Lo adLibrary("libc .so.6")
              >
              <CDLL 'libc.so.6', handle 2a958a2900 at 2a95dda490>>>cd ll.LoadLibrary( "libucdb.so ")
              >
              Traceback (most recent call last):
                File "<stdin>", line 1, in <module>
                File "/software/unix-soft/linux/ActivePython-2.5.1.1-linux-x86_64/
              lib/pyth=
              on2.5/ctypes/__init__.py", line 423, in LoadLibrary
                  return self._dlltype(n ame)
                File "/software/unix-soft/linux/ActivePython-2.5.1.1-linux-x86_64/
              lib/pyth=
              on2.5/ctypes/__init__.py", line 340, in __init__
                  self._handle =3D _dlopen(self._n ame, mode)
              OSError: libucdb.so: cannot open shared object file: No such file or
              directo=
              ry>>cdll.LoadLi brary("libc.so. 6")
              >
              <CDLL 'libc.so.6', handle 2a958a2900 at 2a95df3ad0>>>li bc =3D CDLL("libc.so.6 ")
              >>libc
              >
              <CDLL 'libc.so.6', handle 2a958a2900 at 2a95dda490>>>li bc =3D CDLL("libucdb.s o")
              >
              Traceback (most recent call last):
                File "<stdin>", line 1, in <module>
                File "/software/unix-soft/linux/ActivePython-2.5.1.1-linux-x86_64/
              lib/pyth=
              on2.5/ctypes/__init__.py", line 340, in __init__
                  self._handle =3D _dlopen(self._n ame, mode)
              OSError: libucdb.so: cannot open shared object file: No such file or
              directo=
              ry>>libc =3D CDLL("/opt/questasim_6.4/questasim/linux/libucdb.so")
              >
              Traceback (most recent call last):
                File "<stdin>", line 1, in <module>
                File "/software/unix-soft/linux/ActivePython-2.5.1.1-linux-x86_64/
              lib/pyth=
              on2.5/ctypes/__init__.py", line 340, in __init__
                  self._handle =3D _dlopen(self._n ame, mode)
              OSError: /opt/questasim_6.4/questasim/linux/libucdb.so: cannot open
              shared o=
              bject file: No such file or directory>>^[[A
              >
                File "<stdin>", line 1
                  ^
              SyntaxError: invalid syntax
              >
              - Paddy.
              >
              Any help would be appreciated.
              >
              Thanks.
              What is your current working directory and where is the lib located ?
              Maybe the lib is not in your working directory.

              If you want the lib accessed from anywhere, you have to copy it
              to /usr/lib or /usr/local/lib.
              Another possibility is setting LD_LIBRARY_PATH .

              Greetings, Uwe

                Comment

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