[ctypes-users] in_dll string assignment question

[Ben S. <ben...@gm...>]

I could use some help assigning to global C variable in DLL using ctypes.

test.c contains the following

#include <stdio.h>

char name[60];
void test(void) {
printf("Name is %s\n", name);
}


On windows (cygwin) I build a DLL (test.dll) as follows:

gcc -g -c -Wall test.c
gcc -Wall -mrtd -mno-cygwin -shared -W1,--add-stdcall-alias -o Test.dll 
test.o

Then when trying to modify the `name` variable and then calling the C 
test function using the ctypes interface I get the following...

 >>> from ctypes import *
 >>> dll = windll.Test
 >>> dll
<WinDLL 'Test', handle ... at ...>
 >>> f = c_char_p.in_dll(dll, 'name')
 >>> f
c_char_p(None)
 >>> f.value = 'foo'
 >>> f
c_char_p('foo')
 >>> dll.test()
Name is Name is 4∞┘☺
13

Why does the test function print garbage in this case?