我使用python和ctypes来调用一个cso文件
C结构是:
typedef struct {
uint32_t var1;
uint32_t var2;
uint32_t var3;
uint8_t var4;
uint8_t var5
} struct1;
If I call C code where I set the variables of var1 to 0x050A, var2 to 0x102 and var3 to 0x203 build it and print out the values everything works perfectly.
in C
static struct1 mstruct;
mstruct.var1=1290
mstruct.var2=258
mstruct.var3=515
然后我调用一个c so文件,它打印出传递给它的结构的值
printf("var1 %lx\n",mstruct.var1) # var1 050A
printf("var2 %lx\n",mstruct.var2) # var2 102
printf("var3 %lx\n",mstruct.var3) # var3 203
请注意,如果我只是使用x而不是lx,它将不会生成,并给出一个错误。
但是当从C调用时,所有内容都正确打印出来
var1 050A
var2 102
var3 203
现在,如果我用python初始化并调用相同的结构,我将类定义为:
class struct1(ctypes.Structure):
_fields_=[
('var1',ctypes.c_uint32),
('var2',ctypes.c_uint32),
('var3',ctypes.c_uint32),
('var4',ctypes.c_uint8),
('var5',ctypes.c_uint8)]
def __init__(self):
self.var1=1290
self.var2=258
self.var3=515
if __name__=='__main__':
mstruct=struct1()
print('var1 {} type {}'.format(mstruct.var1,type(mstruct.var1)))
clib=ctypes.CDLL('csofile.so')
c_rtn=clib.print_c_struct(ctypes.byref(mstruct))
Var1值正确,类型打印为“int”类(不是ctypes uint32)。
并在C so文件中打印出
var1 102000050A
var2 50a00000203
var3 20300000102
Var1的最低16位是正确的值。中间的16位用正确的零填充。但是var1中的VAR2应该是一个高32位。Var2从Var3的值开始
似乎有一个不匹配的地方,比如我的python并没有真正将其定义为32位,但奇怪的是C实际上将其读取为64位,我不明白这是怎么回事。由于C结构将其定义为32位,我希望它只需要32位,因此它在python中看到了64位
如果我将所有内容都更改为int,那么它在我的演示应用程序中可以完美工作,但是真正的C so文件是由其他人创建的,我会每隔几天获得一个新文件,所以我尽量避免每次更改它
当我在init中设置值时,我也尝试了强制转换,认为我可能覆盖了类型,但这似乎没有改变任何东西
self.var1=(ctypes_c_uint32)(1290)
任何帮助都将不胜感激
标题:
#include <stdint.h>
typedef struct{
uint32_t first;
uint32_t second;
int *marray;
} my_struct;
int call_c_function(int var1,int *var2, my_struct *mstruct );
C文件
#include <stdio.h>
#include <memory.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include "c_header.h"
int call_c_function(int var1,int *var2, my_struct *mstruct ){
printf("var1 %d \n",var1);
printf("var2 %d \n",*var2);
printf("mystruct first %ld \n",mstruct->first);
printf("mystruct second %ld \n",mstruct->second);
int *array_ptr;
array_ptr = mstruct->marray;
printf("C ADDR struct %p \n",mstruct);
printf("C ADDR of pointer array_ptr %p \n",&array_ptr);
printf("C ADDR stored at array_ptr %p I need Python to match this!\n",array_ptr);
printf("Value in Memory it points to %d \n",*array_ptr);
printf("size of c int %ld\n",sizeof(int));
for (int i=0;i<8;i++){
printf(" %d ",array_ptr[i]);
array_ptr[i]=8-i;
}
printf("\n ");
return 0;
}
使用g++-fPIC-shared-o clib.so c_file.cpp编译 和Python
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Tue Aug 18 13:16:52 2020
@author: kevin.johnson
"""
import ctypes as ctypes
import struct as struct
so_file='./clib.so'
class my_struct(ctypes.Structure):
_fields_=[
('first',ctypes.c_uint32),
('second',ctypes.c_uint32),
('marray',ctypes.POINTER(ctypes.c_int))]
def __init__(self,ma):
self.first=1290
self.second=258
self.marray = ma
def so_attr(sofile):
from subprocess import Popen,PIPE
out = Popen(args='nm ./{}'.format(sofile),
shell=True,
stdout=PIPE).communicate()[0].decode("utf-8")
attrs=[i.split(" ")[-1].replace("\r", "")
for i in out.split("\n") if " T " in i]
functions = [i for i in attrs if hasattr(ctypes.CDLL(sofile),i)]
print (functions)
def arr2list(inp,length):
outp=[inp[i] for i in range(length)]
return outp
if __name__ == '__main__':
if 0:
so_attr(so_file)
else:
mn = [i for i in range(8)]
ms = ctypes.c_int*8
ma = ms(*mn)
print(type(ma))
ma_p = ctypes.cast(ma,ctypes.POINTER(ctypes.c_int))
ma_byref = ctypes.byref(ma)
mstruct_inst=my_struct(ma_p)
print ('size of python int {} '.format(ctypes.sizeof(ma)/len(ma)))
print(mstruct_inst)
print('var1 {} type {}'.format(mstruct_inst.first,type(mstruct_inst.first)))
var1=ctypes.c_int(5)
var2=ctypes.c_int(6)
print(arr2list(ma,8))
clib=ctypes.CDLL(so_file)
print('ADDRESS: {}'.format(ctypes.byref(mstruct_inst)))
print('by ref ma: {} I Need C to match this'.format(ma_byref))
print('map: {}'.format(ma_p))
print('map2: {}'.format(ctypes.cast(ctypes.byref(ma),ctypes.POINTER(ctypes.c_int))))
funct_int=clib._Z15call_c_functioniPiP9my_struct(var1,ctypes.byref(var2),ctypes.byref(mstruct_inst))
print ('C Function return {} '.format(funct_int))
print(arr2list(ma,8))
print('done')
系统上的
long
为64位,如printf("%lx")
打印64位整数所示。正如我在评论中看到的,您的C代码uint32_t
被定义为unsigned long
,这在该系统上是不正确的您的系统应该有一个
stdint.h
头,它为您的操作系统正确定义了uint32_t
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