Illegal stack operations

Illegal Stack Operations

Illegal stack operations can lead to hard to detect crashes. This typically takes place when a program passes a pointer of the wrong type to a function. The example given below shows a case of a function expecting an integer pointer and the caller passes a pointer to a character.

http://www.eventhelix.com/realtimemantra/Basics/debugging_software_crashes.htm

char pointer/int pointer mixup

main() { char count; // The routine expects a int pointer but a char pointer has been passed // Older compilers and non ANSI C compilers do not catch this error GetCount(&count); // The called function was expecting an int (say 4 byte) variable. It was // however passed a char pointer with one byte space. GetCount will still // write four bytes, thus corrupting local variables or parameters on the // stack } bool GetCount(int *pCount) { . . . *pCount = returnValue; return true; }