Question

这是我在解决实际有用问题之前尝试开始工作的一个简单示例。 C代码：

typedef struct {
  uint32_t seconds;
  uint32_t nanoseconds;
} geoTime;

int myTest(geoTime *myTime){
  printf("Time: %d %d\n", myTime->seconds, myTime->nanoseconds);
  myTime->seconds = myTime->nanoseconds;
  geoTime T = {314, 159};
  printf("MyTime: %d %d      retValue: %d %d\n", myTime->seconds, myTime->nanoseconds, T.seconds, T.nanoseconds);
  return 314;
}

Python代码：

import ctypes
import time
import math

lib_astro = ctypes.CDLL("libastroC.so")

class geoTime(ctypes.Structure):
    _fields_ = [("seconds", ctypes.c_uint),
                ("nanoseconds", ctypes.c_uint)]  

now = time.time()
print "Python Now: ", now

now_geoTime = geoTime()
now_geoTime.seconds = ctypes.c_uint(int((math.floor(now))))
now_geoTime.nanoseconds = ctypes.c_uint(int(math.floor(math.modf(now)[0] * 1000000000)))
print "Python geoTime now:", now_geoTime.seconds, now_geoTime.nanoseconds

lib_astro.myTest.argtypes = [ctypes.POINTER(geoTime)]
lib_astro.myTest.restype = geoTime
print "************* ENTERING C ********************"
test = lib_astro.myTest(ctypes.byref(now_geoTime))
print "************* EXITING C **********************"
print "Modified now_geoTime: ",now_geoTime.seconds, now_geoTime.nanoseconds
print "test: ",test

输出：

Python Now:  1336401085.43
Python geoTime now: 1336401085 432585000
************* ENTERING C ********************
Time: 1336401085 432585000
MyTime: 432585000 432585000      retValue: 314 159
************* EXITING C **********************
Modified now_geoTime:  432585000 432585000
test:  314

上面的代码完全按照我的预期工作，我的指针进入并被修改，我得到了我的整数。当我尝试在C中创建一个geoTime结构并将其返回给Python时，就会出现问题。

在C：

中添加/修改了代码

geoTime patTest(geoTime *myTime){
    printf("Time: %d %d\n", myTime->seconds, myTime->nanoseconds);
    myTime->seconds = myTime->nanoseconds;
    geoTime T = {314, 159};
    printf("MyTime: %d %d      retValue: %d %d\n", myTime->seconds, myTime->nanoseconds, T.seconds, T.nanoseconds);
    return T;

}

修改后的Python代码：

lib_astro.patTest.argtypes = [ctypes.POINTER(geoTime)]
lib_astro.patTest.restype = geoTime
print "************* ENTERING C ********************"
test = lib_astro.patTest(ctypes.byref(now_geoTime))
print "************* EXITING C **********************"
print "Modified now_geoTime: ",now_geoTime.seconds, now_geoTime.nanoseconds
print "Type of test: ",test
print "Information in test: ", test.seconds, test.nanoseconds

一旦我更改了我的代码，C代码就会变成myTime而不是来自Python的信息，并且返回值会被放入now_geoTime而不是test。关于可能出错的任何想法？看起来python代码没有像我期望的那样做，因为C代码似乎与传入的值一起正常工作。

上一个例子的输出：

Python Now:  1336404920.77
Python geoTime now: 1336404920 773674011
************* ENTERING C ********************
Time: 90500 -17037640
MyTime: -17037640 -17037640      retValue: 314 159
************* EXITING C **********************
Modified now_geoTime:  314 159
Type of test:  <__main__.geoTime object at 0x82bedf4>
Information in test:  137096800 134497384

任何想法都会受到高度赞赏，我一直试图让它工作很长一段时间。提前谢谢！

Answer 1

我切换到64位python / 64位dll，问题就消失了。当我感觉有点灵感时，我可能会尝试将它分离到编译器，os或python但是现在我将用它来运行。

Python Ctypes传入指针并获得结构

1 个答案: