Idle Time

New series: Manpage FridayMonday. Every Fridayother Monday, I will post a link to one manpage that comes with Mac OS X. [See update below.]

Today, it’s backtrace(3), which tells you about three 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.