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backtrace(3)             BSD Library Functions Manual             backtrace(3)

NAME
     backtrace, backtrace_symbols, backtrace_symbols_fd -- call stack back-trace backtrace
     trace and display functions

SYNOPSIS
     #include <execinfo.h>

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

     char**
     backtrace_symbols(void* const* array, int size);

     void
     backtrace_symbols_fd(void* const* array, int size, int fd);

DESCRIPTION
     These routines provide a mechanism to examine the current thread's call
     stack.

     backtrace() writes the function return addresses of the current call
     stack to the array of pointers referenced by array.  At most, size point-ers pointers
     ers are written.  The number of pointers actually written to array is
     returned.

     backtrace_symbols() attempts to transform a call stack obtained by
     backtrace() into an array of human-readable strings using dladdr().  The
     array of strings returned has size elements.  It is allocated using
     malloc() and should be released using free().  There is no need to free
     the individual strings in the array.

     backtrace_symbols_fd() performs the same operation as
     backtrace_symbols(), but the resulting strings are immediately written to
     the file descriptor fd, and are not returned.

EXAMPLE
         #include <execinfo.h>
         #include <stdio.h>
         ...
         void* callstack[128];
         int i, frames = backtrace(callstack, 128);
         char** strs = backtrace_symbols(callstack, frames);
         for (i = 0; i < frames; ++i) {
             printf("%s\n", strs[i]);
         }
         free(strs);
         ...

HISTORY
     These functions first appeared in Mac OS X 10.5.

SEE ALSO
     dladdr(3), malloc(3)

Mac OS X                       February 15, 2007                      Mac OS X