How can I count the number of callstack frames?

Question

For a C++ debug application I want to be able to count the number of callstack frames easily. Is there an OS function to do this?

I need this for Windows and Posix, i.e. cross platform. Solutions to either or both platforms would be great.

I can walk the stack to find all of the frames but I wondered if there was an easy call to do this.

Answer 1

No, because this is a compiler thing.

The compiler is free to define its own ABI. This defines how the callstack (if any) is defined. Unless you are using pure "C" this is non trivial and will be different for every compiler.

Also I have heard (but have not verified) that MS is using a new scheme were stack frames are placed randomly around memory so as to prevent (make harder) buffer overflow attacks that affect the return jump. Not exactly relevant but a fun fact.

Answer 2

If you use glibc (Linux) you can use the following functions to get the stack trace:

#include <execinfo.h> 
int backtrace(void **buffer, int size); 
char **backtrace_symbols(void *const *buffer, int size); 
void backtrace_symbols_fd(void *const *buffer, int size, int fd);

For more information see the man page for backtrace.