蟒蛇转换字符串对象到C的char *使用ctypes的 [英] Converting python string object to c char* using ctypes

问题描述

我想在Python（3.2）发送2字符串使用C ctypes的。这是我对我的树莓派项目的一小部分。以测试是否C函数正确地接收到的字符串，我把它们中的一个在一个文本文件。

I am trying to send 2 strings from Python (3.2) to C using ctypes. This is a small part of my project on my Raspberry Pi. To test if the C function received the strings correctly, I place one of them in a text file.

的Python code

string1 = "my string 1"
string2 = "my string 2"

# create byte objects from the strings
b_string1 = string1.encode('utf-8')
b_string2 = string2.encode('utf-8')

# send strings to c function
my_c_function(ctypes.create_string_buffer(b_string1),
              ctypes.create_string_buffer(b_string2))

C $ C $ç

void my_c_function(const char* str1, const char* str2)
{
    // Test if string is correct
    FILE *fp = fopen("//home//pi//Desktop//out.txt", "w");
    if (fp != NULL)
    {
        fputs(str1, fp);
        fclose(fp);
    }

    // Do something with strings..
}

问题

只有串的首字母出现在文本文件中。

Only the first letter of the string appears in the text file.

我试过很多方法了Python string对象转换与ctypes的。

I've tried many ways to convert the Python string object with ctypes.

• ctypes.c_char_p


• ctypes.c_wchar_p


• ctypes.create_string_buffer

使用这些转换我不断收到错误错误类型或字节或预期，而不是​​STR例如整数地址。

With these conversions I keep getting the error "wrong type" or "bytes or integer address expected instead of str instance".

我希望有人能告诉我在哪里出了问题。
先谢谢了。

I hope someone can tell me where it goes wrong. Thanks in advance.

推荐答案

由于Eryksun解决方案：

Thanks to Eryksun the solution:

的Python code

string1 = "my string 1"
string2 = "my string 2"

# create byte objects from the strings
b_string1 = string1.encode('utf-8')
b_string2 = string2.encode('utf-8')

# send strings to c function
my_c_function.argtypes = [ctypes.c_char_p, ctypes_char_p]
my_c_function(b_string1, b_string2)

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