我正在使用包含单个调用的.dll,它返回一个函数指针数组。 GetMyApi()返回一个指向结构的指针,该结构是一个函数指针数组。功能本身具有不同的单独输入和输出。到目前为止我尝试过的:
[我不能轻易改变的C代码] C:
typedef struct My_Api_V2
{
int (__cdecl *IsValidInt)(int i);
int (__cdecl *InvalidInt)();
int (__cdecl *IsValidSize)(size_t i);
} my_Api_V2;
const my_Api_V2* GetMyApi(int version); // This function is accessed from DLL
Python努力:
from ctypes import *
my_dll = cdll.LoadLibrary(path_to_my_dll)
my_api = my_dll.GetMyApi
my_api.argtypes[c_int] #version number
my_api.restypes = c_void_p
firstfuncptr = my_api(2)
firstfunc = prototype(firstfuncptr)
firstfunc.argtypes[c_int]
firstfunc.restypes = c_int
test = firstfunc(23)
此时,我只是想让函数列表的第一个函数返回工作。任何帮助指向我更好的方向的人都表示赞赏。
事情并不像第一眼看到的那样容易。我将发布一个虚拟示例,恰好包含使用.dlls(.sos)函数的两种方法(如[Python 3]: ctypes - A foreign function library for Python中所述)。
dll.c:
#include <stdio.h>
#if defined(_WIN32)
# define DLL_EXPORT __declspec(dllexport)
# pragma warning(disable: 4477) // !!! Just to avoid having additional code (macro for size_t), do NOT do this !!!
#else
# define DLL_EXPORT
#endif
#define PRINT_MSG_0() printf(" [%s] (%d) - [%s]\n", __FILE__, __LINE__, __FUNCTION__)
#define PRINT_MSG_1I(ARG0) printf(" [%s] (%d) - [%s]: ARG0: %d\n", __FILE__, __LINE__, __FUNCTION__, ARG0)
static int IsValidInt(int i) {
PRINT_MSG_1I(i);
return -i;
}
static int InvalidInt() {
PRINT_MSG_0();
return 0;
}
static int IsValidSize (size_t i) {
PRINT_MSG_1I(i);
return -i;
}
typedef struct DllInterfaceV2Struct {
int (__cdecl *IsValidIntFuncPtr)(int i);
int (__cdecl *InvalidIntFuncPtr)();
int (__cdecl *IsValidSizeFuncPtr)(size_t i);
} DllInterfaceV2;
static DllInterfaceV2 intfV2 = {IsValidInt, InvalidInt, IsValidSize};
#if defined(__cplusplus)
extern "C" {
#endif
DLL_EXPORT const DllInterfaceV2 *GetInterfaceV2(int version);
#if defined(__cplusplus)
}
#endif
DLL_EXPORT const DllInterfaceV2 *GetInterfaceV2(int version) {
if (version == 2) {
return &intfV2;
} else {
return NULL;
}
}
code.朋友:
#!/usr/bin/env python3
import sys
import ctypes
DLL_NAME = "test.dll"
DLL_FUNC_NAME = "GetInterfaceV2"
# "Define" the Python counterparts for C stuff in order to be able to use it
IsValidIntFuncPtr = ctypes.CFUNCTYPE(ctypes.c_int, ctypes.c_int)
InvalidIntFuncPtr = ctypes.CFUNCTYPE(ctypes.c_int)
IsValidSizeFuncPtr = ctypes.CFUNCTYPE(ctypes.c_int, ctypes.c_size_t)
class DllInterfaceV2(ctypes.Structure):
_fields_ = [
("is_valid_int", IsValidIntFuncPtr),
("invalid_int", InvalidIntFuncPtr),
("is_valid_size", IsValidSizeFuncPtr)
]
# Now, play with C stuff
def test_interface_ptr(intf_ptr):
print("Testing returned interface: {:}\n".format(intf_ptr))
if not intf_ptr:
print(" NULL pointer returned from C\n")
return
intf = intf_ptr.contents # Dereference the pointer
res = intf.is_valid_int(-2718281)
print(" `is_valid_int` member returned: {:d}\n".format(res))
res = intf.invalid_int()
print(" `invalid_int` member returned: {:d}\n".format(res))
res = intf.is_valid_size(3141592)
print(" `is_valid_size` member returned: {:d}\n\n".format(res))
def main():
test_dll = ctypes.CDLL(DLL_NAME)
get_interface_v2_func = getattr(test_dll, DLL_FUNC_NAME) # Or simpler: test_dll.GetInterfaceV2
get_interface_v2_func.argtypes = [ctypes.c_int]
get_interface_v2_func.restype = ctypes.POINTER(DllInterfaceV2)
pintf0 = get_interface_v2_func(0)
test_interface_ptr(pintf0)
pintf2 = get_interface_v2_func(2)
test_interface_ptr(pintf2)
if __name__ == "__main__":
print("Python {:s} on {:s}\n".format(sys.version, sys.platform))
main()
笔记:
输出:
(py35x64_test) e:\Work\Dev\StackOverflow\q051507196>"c:\Install\x86\Microsoft\Visual Studio Community\2015\vc\vcvarsall.bat" x64 (py35x64_test) e:\Work\Dev\StackOverflow\q051507196>dir /b code.py dll.c (py35x64_test) e:\Work\Dev\StackOverflow\q051507196>cl /nologo dll.c /link /DLL /OUT:test.dll dll.c Creating library test.lib and object test.exp (py35x64_test) e:\Work\Dev\StackOverflow\q051507196>dir /b code.py dll.c dll.obj test.dll test.exp test.lib (py35x64_test) e:\Work\Dev\StackOverflow\q051507196>"e:\Work\Dev\VEnvs\py35x64_test\Scripts\python.exe" code.py Python 3.5.4 (v3.5.4:3f56838, Aug 8 2017, 02:17:05) [MSC v.1900 64 bit (AMD64)] on win32 Testing returned interface: <__main__.LP_DllInterfaceV2 object at 0x00000219984EBAC8> NULL pointer returned from C Testing returned interface: <__main__.LP_DllInterfaceV2 object at 0x00000219984EBB48> [dll.c] (16) - [IsValidInt]: ARG0: -2718281 `is_valid_int` member returned: 2718281 [dll.c] (22) - [InvalidInt] `invalid_int` member returned: 0 [dll.c] (28) - [IsValidSize]: ARG0: 3141592 `is_valid_size` member returned: -3141592