dl
— 调用共享对象中的 C 函数
¶
Deprecated since version 2.6:
The
dl
module has been removed in Python 3. Use the
ctypes
模块代替。
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 arbitrary functions in such a library.
警告
The
dl
module bypasses the Python type system and error handling. If used incorrectly it may cause segmentation faults, crashes or other incorrect behaviour.
注意
This module will not work unless
sizeof(int) == sizeof(long) == sizeof(char
*)
If this is not the case,
SystemError
will be raised on import.
The
dl
模块定义以下函数：
dl.
open
(
名称
[
,
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 systems do not support
RTLD_NOW
.
Return value is a
dlobject
.
The
dl
module defines the following constants:
dl.
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
模块定义以下异常：
dl.
error
¶
Exception raised when an error has occurred inside the dynamic loading and linking routines.
范例：
>>> 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.
Dl objects, as returned by
open()
above, have the following methods:
dl.
close
(
)
¶
Free all resources, except the memory.
dl.
sym
(
名称
)
¶
Return the pointer for the function named
name
, as a number, if it exists in the referenced shared object, otherwise
None
. This is useful in code like:
>>> if a.sym('time'): ... a.call('time') ... else: ... time.time()
(Note that this function will return a non-zero number, as zero is the NULL pointer)
dl.
call
(
名称
[
,
arg1
[
,
arg2...
]
]
)
¶
Call the function named
name
in the referenced shared object. The arguments must be either Python integers, which will be passed as is, Python strings, to which a pointer will be passed, or
None
, which will be passed as
NULL
. Note that strings should only be passed to functions as
const char*
, as Python will not like its string mutated.
There must be at most 10 arguments, and arguments not given will be treated as
None
. The function’s return value must be a C
long
, which is a Python integer.