WindowsError: exception: access violation

Benjamin Kaplan benjamin.kaplan at
Fri Jul 22 04:17:49 CEST 2011

On Thu, Jul 21, 2011 at 6:42 PM, Sathish S <sathish at> wrote:
> Hi Ppl,
>  I have been trying to call a C DLL built in GCC with cygwin and Eclipse IDE
> from python. Since this DLL was built using cygwin it had the following two
> DLL's as dependency. cygwin1.dll and cyggcc_s-1.dll
> I'm calling the cygwin_dll_init method in the cygwin1.dll before accessing
> my DLL. When I call one of the methods within my DLL I get the WindowsError:
> exception: access violation... error
> the functions prototype is like: int function(char *, char *) I'm calling
> the function as: DLL = cdll.LoadLibrary (DLL_NAME) print
> DLL.function(c_char_p("string1"),c_char_p("string2)")
> This error is not consistent with all the stations. I occurs consistently in
> many XP machines, while in Windows 7, this occurs once in a while. In Win 7
> in starts up a Pythonw.exe process when calling function successfully. I'm
> not sure why this error occurs. Any help ??

An access violation is what is usually referred to as a seg fault. It
means something isn't getting initialized properly. Are you using a
Cygwin build of Python? Trying to mix Cygwin with normal Windows
programs doesn't usually work very well.

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