Python Library Reference

Next: 8.5.1 Dl Objects Up: 8. Unix Specific Services Previous: 8.4 crypt

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8.5 dl -- Call C functions in shared objects

Availability: Unix.

The dl module defines an interface to the dlopen() function, which is the most common interface on Unix platforms for handling dynamically linked libraries. It allows the program to call arbitary functions in such a library.

Note: This module will not work unless

sizeof(int) == sizeof(long) == sizeof(char *)

The dl module defines the following function:

open (name[, mode = RTLD_LAZY])

Open a shared object file, and return a handle. Mode signifies late binding (RTLD_LAZY) or immediate binding (RTLD_NOW). Default is RTLD_LAZY. Note that some sytems do not support RTLD_NOW.

Return value is a dlobject.

The dl module defines the following constants:

RTLD_LAZY

Useful as an argument to open().

RTLD_NOW

Useful as an argument to open(). Note that on systems which do not support immediate binding, this constant will not appear in the module. For maximum portability, use hasattr() to determine if the system supports immediate binding.

The dl module defines the following exception:

error

Exception raised when an error has occured inside the dynamic loading and linking routines.

Example:

>>> import dl, time
>>> a=dl.open('/lib/libc.so.6')
>>> a.call('time'), time.time()
(929723914, 929723914.498)

This example was tried on a Debian GNU/Linux system, and is a good example of the fact that using this module is usually a bad alternative.

• 8.5.1 Dl Objects

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Python Library Reference

Next: 8.5.1 Dl Objects Up: 8. Unix Specific Services Previous: 8.4 crypt