Question

I have a python program which calls a C function. I send some structures containing mutable characters to c functions and my c function fills the structure.

class myS(Structure):
fields = [(“x”, c_int),
(“buffer”, 100*c_char)]

I send this to C function and C function fills the value in this structure. My program works very fine but after return it throws an error

* glibc detected * python: free(): invalid next size (fast):

Subsequent execution of program shows one of the following 3 errors on little change in code(such as print “hi”).

* glibc detected * python: malloc(): invalid next size (fast):

* glibc detected * python: free(): invalid next size (fast):

segmentation fault

Please help me out. Thanks in advance.

Answer 1

You have corrupted the memory arena, plain and simple, possibly by writing beyond the end of the memory that was passed to the C function but, without seeing the source code, we’ll never know for sure.

That message only appears when glib detects that the memory allocation accounting information has been corrupted.