Python Ctypes传入指针并获得结构
这是我在解决实际有用问题之前尝试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geoTime结构并将其返回到Python时，会出现问题。
在C中添加/修改代码：
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，并且返回值将被放入now_geoTime而不是test。 什么可能出错？ 看起来python代码没有像我期望的那样做某事，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: Information in test: 137096800 134497384
任何想法都会非常感激，我一直试图让它工作一段时间。 提前致谢！
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。