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

NAME

     backtrace, backtrace_symbols, backtrace_symbols_fd -- call stack backtrace 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
     pointers 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
", 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