[charrisTTI]

The stack is used in C whenever a function is called. The compiler can use it for passing parameters, storing the address at which execution will resume when the function returns, and temporary storage for local variables (those declared within a function). The stack is a limited resource. Stack overflow can occur if your function call depth is too great. Function A calls B, B calls C, C calls ...., you get the idea. At some point you will run out of stack space.
A recursive function (one which calls itself) can generate a stack overflow if it has an error which causes an infinite loop or simply is called recursively so many times that all space is used (as described above).

Post some code if you would like further analysis.