unw_backtrace - Man Page

#include <libunwind.h>

int unw_backtrace(void **buffer, int size);
int unw_backtrace2(void **buffer, int size, unw_context_t *ctxt, int flag);

#include <execinfo.h>

int backtrace(void **buffer, int size);

unw_backtrace() is a convenient routine for obtaining the backtrace for  the calling program. The routine fills up to size addresses in the array  pointed by buffer. The routine is only available for local unwinding.

Note that many (but not all) systems provide a practically identical function  called backtrace(). The prototype for this function is usually obtained  by including the <execinfo.h> header file -- a prototype for  backtrace() is not provided by libunwind. libunwind weakly  aliases backtrace() to unw_backtrace(), so when a program  calling backtrace() is linked against libunwind, it may end up  calling unw_backtrace().

In case you want to obtain the backtrace from a specific unw_context_t, you can call unw_backtrace2 with that context passing 0 for flag.  If the unw_context_t is known to be a signal frame (i.e., from the third argument  in a sigaction handler on linux), unw_backtrace2 can be used to collect  only the frames before the signal frame passing the UNW_INIT_SIGNAL_FRAME flag.

The routine returns the number of addresses stored in the array pointed by  buffer. The return value may be zero to indicate that no addresses were  stored.

libunwind(3libunwind), unw_step(3libunwind)

David Mosberger-Tang
Email: dmosberger@gmail.com
WWW: http://www.nongnu.org/libunwind/.