Unhandled exception at 0x6c70f2ca in xxx.exe 0xC0000005: Access violation reading location 0xcdcdcdf1 how to debug this?

Question

Hello i have c application that im compiling in visual studio 2010
im getting this error in one of my functions generically how can i debug this kind of exception ?
the function is from dll , other functions working but not this one .

Answer 1

The error most likely happens when trying to dereference an uninitialized pointer. So:

1. Recompile with warning level on maximum (4). Review the warnings. You'll find listed the local variables that are declared without initialization (including pointers).
2. Check the parameters you pass to the function (especially the pointer/reference parameters). Check their initialization.

Answer 2

The debug memory allocator fills newly-allocated memory with 0xcdcdcdcd. It looks like you've allocated some memory, only set the low byte to 0xf1 (241), and tried to derefence a four-byte pointer at that location. Without seeing code, that's as much as I can discern.