Question

我想从Python调用DLL中的函数。但是我收到了这个错误：

"Attribute Error function not found"

这是我的代码：

import os
import ctypes


os.chdir("C:\\Program Files\\Compact Automated Testing System V2.0")    

# Load DLL into memory. 
CATSDll = ctypes.WinDLL ("CATS.dll")

# Set up prototype and parameters for the desired function call. 
CATSDllApiProto = ctypes.WINFUNCTYPE (ctypes.c_uint8,ctypes.c_double) 

CATSDllApiParams = (1, "p1", 0), (1, "p2", 0), 

# Actually map the call (setDACValue) to a Python name.
CATSDllApi = CATSDllApiProto (("setDACValue", CATSDll), CATSDllApiParams)

# Set up the variables and call the Python name with them. 
p1 = ctypes.c_uint8 (1)
p2 = ctypes.c_double (4)

CATSDllApi(p1,p2)

但DLL文档显示了setDACValue函数ChannelId和DAC Voltage＆amp; Traceback (most recent call last): File "C:\Users\AEC_FULL\Softwares\eclipse\plugins\org.python.pydev_3.9.2.201502050007\pysrc\pydevd.py", line 2235, in <module> globals = debugger.run(setup['file'], None, None) File "C:\Users\AEC_FULL\Softwares\eclipse\plugins\org.python.pydev_3.9.2.201502050007\pysrc\pydevd.py", line 1661, in run pydev_imports.execfile(file, globals, locals) # execute the script File "C:\Users\AEC_FULL\Saravanan\Workspace\CATS\CATS.py", line 18, in <module> CATSDllApi = CATSDllApiProto (("setDACValue", CATSDll), CATSDllApiParams) AttributeError: function 'setDACValue' not found作为输入。

以上内容基于StackOverflow提供的一段代码。

我也尝试过使用cdll.LoadLibrary＆amp;的简单方法。然后调用该函数，但也会出现相同的错误。

有谁能告诉我什么是错的？感谢。

完整追溯：

    class func signUp(username : String , completion: (status : NSString)->Void) {
    var url: NSURL = NSURL(string: "http://localhost/WhosIn/signup.php")!
    var request:NSMutableURLRequest = NSMutableURLRequest(URL:url)
    var bodyData = "username=Datforis&name=firas&password=123"
    request.HTTPMethod = "POST"
    request.HTTPBody = bodyData.dataUsingEncoding(NSUTF8StringEncoding);
    var status = "error"
    NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.mainQueue())
        {

            (response, data, error) in
            println(response)
            if(error != nil){
                completion(status: status)
            }
            else if data == nil {
                println("Server could not be reached please check your internet connection")
                status = "connectionerror"
                completion(status: status)
            }
            else {
                println("i'm here")
                let json = JSON(data : data)
                var msgint : Int = json["status"].int!
                status = String(msgint)
                println(status)
                completion(status: status)
            }
        }
}

Signature of the setDACValue

Answer 1

当你指定函数的原型时，你不仅要指定参数的类型，还要指定返回类型作为WINFUNCTYPE的第一个arg。因此，行

CATSDllApiProto = ctypes.WINFUNCTYPE (ctypes.c_uint8,ctypes.c_double)

应替换为

CATSDllApiProto = ctypes.WINFUNCTYPE (ctypes.c_uint8, ctypes.c_uint8,ctypes.c_double)

Answer 2

试试这个。您可能需要使用WinDLL，但更有可能使用CDLL：

from ctypes import *

cats = CDLL('CATS')
cats.setDACValue.argtypes = [c_uint8,c_double]
cats.setDACValue.restype = c_uint8

cats.setDACValue(1,4)

如果仍无法找到setDACValue，则可以使用Microsoft工具dumpbin列出DLL中导出的函数名称：

dumpbin /exports CATS.dll

Visual Studio安装在安装目录下的VC \ bin目录中。

从Python调用DLL函数

2 个答案: